User equipment shift randomization for uplink control channel transmission

ABSTRACT

Methods, systems, and devices for wireless communications are described. In some cases, randomized shifts of a base sequence may be used for transmitting uplink control information. For example, a user equipment (UE) may identify a base sequence of an uplink control message. The UE may also receive signaling that indicates a UE-specific initial shift that may be applied to the base sequence. In some examples, the signaling that indicates the randomized shift may be explicit, implicit, or a combination thereof. After determining one or more shifted sequences based on the UE-specific initial shift, a payload of the uplink control message, and the base sequence, the UE may select a shifted sequence to be transmitted, where the selection is based on a payload of the uplink control message. For example, different shifted sequences may be selected for respective transmissions of scheduling requests, 1-bit acknowledgments (ACKs), 2-bit ACKs, and the like.

CROSS REFERENCES

The present Application for Patent claims benefit of U.S. ProvisionalPatent Application No. 62/592,391 by Wang et al., entitled “UserEquipment Shift Randomization for Uplink Control Channel Format 0 in NewRadio,” filed Nov. 29, 2017, assigned to the assignee hereof, andexpressly incorporated by reference in its entirety.

BACKGROUND

The following relates generally to wireless communication, and morespecifically to user equipment shift randomization for uplink controlchannel format transmission.

Wireless communications systems are widely deployed to provide varioustypes of communication content such as voice, video, packet data,messaging, broadcast, and so on. These systems may be capable ofsupporting communication with multiple users by sharing the availablesystem resources (e.g., time, frequency, and power). Examples of suchmultiple-access systems include fourth generation (4G) systems such asLong Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, orLTE-A Pro systems, and fifth generation (5G) systems which may bereferred to as New Radio (NR) systems. These systems may employtechnologies such as code division multiple access (CDMA), time divisionmultiple access (TDMA), frequency division multiple access (FDMA),orthogonal frequency division multiple access (OFDMA), or discreteFourier transform-spread-orthogonal frequency-division multiplexing(DFT-S-OFDM). A wireless multiple-access communications system mayinclude a number of base stations or network access nodes, eachsimultaneously supporting communication for multiple communicationdevices, which may be otherwise known as user equipment (UE).

UEs in a wireless system may transmit uplink control information to abase station (e.g., for scheduling requests, hybrid automatic repeatrequest (HARD) feedback, or the like), where each UE may utilize aphysical uplink control channel (PUCCH) for the transmission. However,when multiple UEs are multiplexed on resources within a cell, the uplinkcontrol information transmissions by different UEs may cause inter-cellinterference.

SUMMARY

The described techniques relate to improved methods, systems, devices,or apparatuses that support user equipment (UE) shift randomization foruplink control channel transmission. Generally, the described techniquesprovide for the use of shifts of a base sequence used for transmittinguplink control information. For example, a UE may identify a basesequence that is used for the transmission of an uplink control message.The UE may also receive signaling that indicates a UE-specific initialshift that may be used with (e.g., applied to) the identified basesequence. In some cases, the signaling may be explicit (e.g., using anumber of bits in a received control message) or may be implicit basedon a mapping of a control channel element (CCE) index. In otherexamples, there may be a combination of explicit and implicit mappingused for the indication of the initial shift. In some examples, the UEmay determine uplink control information and determine a shiftedsequence of the base sequence based on the UE-specific initial shift andthe uplink control information. For example, different shifted sequencesmay be used for transmissions of scheduling requests, 1-bitacknowledgments (ACKs), 2-bit ACKs, and the like. The UE may transmitthe uplink control information in the uplink control message based onthe shifted sequence. A base station may receive the shifted sequencefrom the UE (e.g., the uplink control information in the uplink controlmessage) and may also receive different shifted sequences from otherUEs. Due to the shifts of the base sequence, the same UEs are likely tonot interfere with each other; while interference between multiple UEsmay still be possible, the randomized shifts result in the avoidance ofinterference between UEs that would normally interfere with each other'suplink transmissions if the shifts were not randomized (but were alwaysthe same).

A method of wireless communication is described. The method may includeidentifying a base sequence for transmission of an uplink controlmessage, receiving signaling that indicates a UE-specific initial shiftto be used with the base sequence, determining uplink controlinformation for the uplink control message, determining a shiftedsequence of the base sequence based on the UE-specific initial shift andthe uplink control information, and transmitting the uplink controlinformation in the uplink control message, where the uplink controlinformation is based on the shifted sequence.

An apparatus for wireless communication is described. The apparatus mayinclude a processor, memory in electronic communication with theprocessor, and instructions stored in the memory. The instructions maybe executable by the processor to cause the apparatus to identify a basesequence for transmission of an uplink control message, receivesignaling that indicates a UE-specific initial shift to be used with thebase sequence, determine uplink control information for the uplinkcontrol message, determine a shifted sequence of the base sequence basedon the UE-specific initial shift and the uplink control information, andtransmit the uplink control information in the uplink control message,where the uplink control information is based on the shifted sequence.

Another apparatus for wireless communication is described. The apparatusmay include means for identifying a base sequence for transmission of anuplink control message, receiving signaling that indicates a UE-specificinitial shift to be used with the base sequence, determining uplinkcontrol information for the uplink control message, determining ashifted sequence of the base sequence based on the UE-specific initialshift and the uplink control information, and transmitting the uplinkcontrol information in the uplink control message, where the uplinkcontrol information is based on the shifted sequence.

A non-transitory computer-readable medium storing code for wirelesscommunication is described. The code may include instructions executableby a processor to identify a base sequence for transmission of an uplinkcontrol message, receive signaling that indicates a UE-specific initialshift to be used with the base sequence, determine uplink controlinformation for the uplink control message, determine a shifted sequenceof the base sequence based on the UE-specific initial shift and theuplink control information, and transmit the uplink control informationin the uplink control message, where the uplink control information isbased on the shifted sequence.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for identifying that apayload of the uplink control information may be one of a schedulingrequest (SR), a one-bit acknowledgement, or a two-bit acknowledgement,and determining the shifted sequence based on the identified payload.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the uplink control messagemay be formatted as a short physical uplink control channel message, andwhere the payload of the uplink control information includes the one-bitacknowledgment or the two-bit acknowledgment.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the payload of the uplinkcontrol information may include operations, features, means, orinstructions for determining the shifted sequence based on a shift valuethat corresponds to the payload the uplink control information, theshift value including a value of 0 or 6.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the uplink controlinformation may include operations, features, means, or instructions fordetermining the shifted sequence based on a shift value that correspondsto the payload the uplink control information, the shift value includinga value of 0, 3, 6, or 9.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, determining the uplinkcontrol information may include operations, features, means, orinstructions for determining a size of acknowledgment information in theuplink control information.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, receiving the signaling thatindicates the UE-specific initial shift may include operations,features, means, or instructions for receiving an explicit indication ofthe UE-specific initial shift.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the explicit indication maybe included within ACK resource indicator (ARI) bits of a DCI message.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, a number of the ARI bits maybe sufficiently large such that two raised to the number of the ARI bitsmay be greater than a number of resources configured for the uplinkcontrol message.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, receiving the signaling thatindicates the UE-specific initial shift may include operations,features, means, or instructions for receiving a downlink grant controlmessage having a CCE index from which the UE-specific initial shift maybe derived.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for deriving an RB indexand a shift index for the UE-specific initial shift based on the CCEindex of the downlink grant control message.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, receiving the signaling thatindicates the UE-specific initial shift may include operations,features, means, or instructions for receiving an explicit indication ofa subset of resources configured for the uplink control message,receiving a downlink grant control message having a CCE index, andderiving a RB index and a shift index for the UE-specific initial shiftbased on the CCE index as applied to the subset of resources.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the explicit indication maybe included within ARI bits of a DCI message.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, a number of the ARI bits maybe such that two raised to the number of the ARI bits may be less than anumber of resources configured for the uplink control message.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining one or moreshifted sequences based on the UE-specific initial shift and the uplinkcontrol information, and selecting the shifted sequence from the one ormore shifted sequences based on a payload of the uplink control message.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for randomizing theselecting of the shifted sequence from the one or more shiftedsequences.

A method of wireless communication is described. The method may includetransmitting, to a UE, signaling that indicates a UE-specific initialshift to be applied to a base sequence for transmission of an uplinkcontrol message and receiving uplink control information in the uplinkcontrol message, where the uplink control information is based on ashifted sequence that is shifted with respect to the base sequence inaccordance with the UE-specific initial shift and a payload of theuplink control information.

An apparatus for wireless communication is described. The apparatus mayinclude a processor, memory in electronic communication with theprocessor, and instructions stored in the memory. The instructions maybe executable by the processor to cause the apparatus to transmit, to aUE, signaling that indicates a UE-specific initial shift to be appliedto a base sequence for transmission of an uplink control message andreceive uplink control information in the uplink control message, wherethe uplink control information is based on a shifted sequence that isshifted with respect to the base sequence in accordance with theUE-specific initial shift and a payload of the uplink controlinformation.

Another apparatus for wireless communication is described. The apparatusmay include means for transmitting, to a UE, signaling that indicates aUE-specific initial shift to be applied to a base sequence fortransmission of an uplink control message and receiving uplink controlinformation in the uplink control message, where the uplink controlinformation is based on a shifted sequence that is shifted with respectto the base sequence in accordance with the UE-specific initial shiftand a payload of the uplink control information.

A non-transitory computer-readable medium storing code for wirelesscommunication is described. The code may include instructions executableby a processor to transmit, to a UE, signaling that indicates aUE-specific initial shift to be applied to a base sequence fortransmission of an uplink control message and receive uplink controlinformation in the uplink control message, where the uplink controlinformation is based on a shifted sequence that is shifted with respectto the base sequence in accordance with the UE-specific initial shiftand a payload of the uplink control information.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the uplink control messagemay be formatted as a short physical uplink control channel message, andwhere the payload of the uplink control information includes a one-bitacknowledgment or a two-bit acknowledgment.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, transmitting the signalingthat indicates the UE-specific initial shift may include operations,features, means, or instructions for transmitting an explicit indicationof the UE-specific initial shift.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the explicit indication maybe included within ARI bits of a DCI message.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, a number of the ARI bits maybe sufficiently large such that two raised to the number of the ARI bitsmay be greater than a number of resources configured for the uplinkcontrol message.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for transmitting additionalsignaling to different UEs, the additional signaling indicatingdifferent UE-specific initial shifts to be applied to the base sequenceby each of the different UEs such that interference betweentransmissions of uplink control messages may be randomized.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, transmitting the signalingthat indicates the UE-specific initial shift may include operations,features, means, or instructions for transmitting a downlink grantcontrol message having a CCE index from which the UE-specific initialshift may be derived.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, transmitting the signalingthat indicates the UE-specific initial shift may include operations,features, means, or instructions for transmitting an explicit indicationof a subset of resources configured for the uplink control message, andtransmitting a downlink grant control message having a CCE index suchthat a RB index and shift index for the UE-specific initial shift may beable to be derived based on the CCE index as applied to the subset ofresources.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the explicit indication maybe included within ARI bits of a DCI message.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, a number of the ARI bits maybe such that two raised to the number of the ARI bits may be less than anumber of resources configured for the uplink control message.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a system for wireless communicationthat supports user equipment (UE) shift randomization for uplink controlchannel transmission in accordance with aspects of the presentdisclosure.

FIGS. 2A and 2B illustrate examples of hypotheses and UE-specific shiftsin a system that supports UE shift randomization for uplink controlchannel transmission in accordance with aspects of the presentdisclosure.

FIG. 3 illustrates an example of a process flow that supports UE shiftrandomization for uplink control channel transmission in accordance withaspects of the present disclosure.

FIGS. 4 through 6 show block diagrams of a device that supports UE shiftrandomization for uplink control channel transmission in accordance withaspects of the present disclosure.

FIG. 7 illustrates a block diagram of a system including a UE thatsupports UE shift randomization for uplink control channel transmissionin accordance with aspects of the present disclosure.

FIGS. 8 through 10 show block diagrams of a device that supports UEshift randomization for uplink control channel transmission inaccordance with aspects of the present disclosure.

FIG. 11 illustrates a block diagram of a system including a base stationthat supports UE shift randomization for uplink control channeltransmission in accordance with aspects of the present disclosure.

FIGS. 12 through 13 illustrate methods for UE shift randomization foruplink control channel transmission in accordance with aspects of thepresent disclosure.

DETAILED DESCRIPTION

User equipment (UEs) in a wireless system may transmit uplink controlinformation to a base station. For example, a UE may transmit ascheduling request (SR), or feedback information (e.g., hybrid automaticrepeat request (HARQ feedback) using uplink control informationtransmitted on a physical uplink control channel (PUCCH). However, insome cases, when multiple UEs are multiplexed on the same resources(where a resource may be uniquely identified with a different symbolindex, different resource block (RB) index, and a different shift index)within a cell, the uplink control information transmissions by differentUEs may cause intra-cell interference. For instance, there may beintra-cell interference among multiple UEs for PUCCH transmissions usingFormat 0 (which may have only one or two uplink control information(UCI) bits), such as when the UEs from the same cell are multiplexed inthe same RB.

As described herein, techniques may be utilized to randomize sequencesused for uplink control information such that intra-cell interference ismitigated between different UEs. For example, there may a randomizationof the shifts used for the transmission of sequence-based uplink controlmessages, which may also randomize the interference using low-complexitytechniques. In some cases, the shifts for sequence-based controlmessages may be UE-specific, and may be indicated according to varioustechniques. For instance, an initial shift may be explicitly indicated,or implicitly mapped, or a combination thereof. In some examples, theremay be an explicit indication of a shift using a certain number of bitsin a downlink control message. In such cases, acknowledgment/negativeacknowledgment (ACK/NACK) resource indicator (ARI) bits may be used forthe explicit indication of the random initial shift. Additionally oralternatively, there may be an implicit mapping based on a CCE index ofa downlink grant control message (e.g., received by the UE on a physicaldownlink control channel (PDCCH)). In other examples, the indication maybe provided via radio resource control (RRC) signaling. Additionally oralternatively, there may be a combination of explicit and implicitmapping, where a subset of resources may be explicitly indicated, and aparticular resource within the subsets may be implicitly mapped (e.g.,to the CCE index), and a shifted sequence may be determined from theparticular resource (e.g., based at least in part on a symbol index).

Aspects of the disclosure are initially described in the context of awireless communications system. Aspects of the disclosure are furtherillustrated by and described with reference to apparatus diagrams,system diagrams, and flowcharts that relate to UE shift randomizationfor uplink control channel transmission.

FIG. 1 illustrates an example of a wireless communications system 100 inaccordance with various aspects of the present disclosure. The wirelesscommunications system 100 includes base stations 105, UEs 115, and acore network 130. In some examples, the wireless communications system100 may be a Long Term Evolution (LTE) network, an LTE-Advanced (LTE-A)network, an LTE-A Pro network, or an NR network. In some cases, wirelesscommunications system 100 may support enhanced broadband communications,ultra-reliable (e.g., mission critical) communications, low latencycommunications, or communications with low-cost and low-complexitydevices.

Base stations 105 may wirelessly communicate with UEs 115 via one ormore base station antennas. Base stations 105 described herein mayinclude or may be referred to by those skilled in the art as a basetransceiver station, a radio base station, an access point, a radiotransceiver, a NodeB, an eNodeB (eNB), a next-generation Node B orgiga-nodeB (either of which may be referred to as a gNB), a Home NodeB,a Home eNodeB, or some other suitable terminology. Wirelesscommunications system 100 may include base stations 105 of differenttypes (e.g., macro or small cell base stations). The UEs 115 describedherein may be able to communicate with various types of base stations105 and network equipment including macro eNBs, small cell eNBs, gNBs,relay base stations, and the like.

Each base station 105 may be associated with a particular geographiccoverage area 110 in which communications with various UEs 115 issupported. Each base station 105 may provide communication coverage fora respective geographic coverage area 110 via communication links 125,and communication links 125 between a base station 105 and a UE 115 mayutilize one or more carriers. Communication links 125 shown in wirelesscommunications system 100 may include uplink transmissions from a UE 115to a base station 105, or downlink transmissions from a base station 105to a UE 115. Downlink transmissions may also be called forward linktransmissions while uplink transmissions may also be called reverse linktransmissions.

The geographic coverage area 110 for a base station 105 may be dividedinto sectors making up only a portion of the geographic coverage area110, and each sector may be associated with a cell. For example, eachbase station 105 may provide communication coverage for a macro cell, asmall cell, a hot spot, or other types of cells, or various combinationsthereof. In some examples, a base station 105 may be movable andtherefore provide communication coverage for a moving geographiccoverage area 110. In some examples, different geographic coverage areas110 associated with different technologies may overlap, and overlappinggeographic coverage areas 110 associated with different technologies maybe supported by the same base station 105 or by different base stations105. The wireless communications system 100 may include, for example, aheterogeneous LTE/LTE-A/LTE-A Pro or NR network in which different typesof base stations 105 provide coverage for various geographic coverageareas 110.

The term “cell” refers to a logical communication entity used forcommunication with a base station 105 (e.g., over a carrier), and may beassociated with an identifier for distinguishing neighboring cells(e.g., a physical cell identifier (PCID), a virtual cell identifier(VCID), etc.) operating via the same or a different carrier. In someexamples, a carrier may support multiple cells, and different cells maybe configured according to different protocol types (e.g., machine-typecommunication (MTC), narrowband Internet-of-Things (NB-IoT), enhancedmobile broadband (eMBB), or others) that may provide access fordifferent types of devices. In some cases, the term “cell” may refer toa portion of a geographic coverage area 110 (e.g., a sector) over whichthe logical entity operates.

UEs 115 may be dispersed throughout the wireless communications system100, and each UE 115 may be stationary or mobile. A UE 115 may also bereferred to as a mobile device, a wireless device, a remote device, ahandheld device, or a subscriber device, or some other suitableterminology, where the “device” may also be referred to as a unit, astation, a terminal, or a client. A UE 115 may also be a personalelectronic device such as a cellular phone, a personal digital assistant(PDA), a tablet computer, a laptop computer, or a personal computer. Insome examples, a UE 115 may also refer to a wireless local loop (WLL)station, an Internet of Things (IoT) device, an Internet of Everything(IoE) device, or an MTC device, or the like, which may be implemented invarious articles such as appliances, vehicles, meters, or the like.

Some UEs 115, such as MTC or IoT devices, may be low cost or lowcomplexity devices, and may provide for automated communication betweenmachines (e.g., via Machine-to-Machine (M2M) communication). M2Mcommunication or MTC may refer to data communication technologies thatallow devices to communicate with one another or a base station 105without human intervention. In some examples, M2M communication or MTCmay include communications from devices that integrate sensors or metersto measure or capture information and relay that information to acentral server or application program that can make use of theinformation or present the information to humans interacting with theprogram or application. Some UEs 115 may be designed to collectinformation or enable automated behavior of machines. Examples ofapplications for MTC devices include smart metering, inventorymonitoring, water level monitoring, equipment monitoring, healthcaremonitoring, wildlife monitoring, weather and geological eventmonitoring, fleet management and tracking, remote security sensing,physical access control, and transaction-based business charging.

Some UEs 115 may be configured to employ operating modes that reducepower consumption, such as half-duplex communications (e.g., a mode thatsupports one-way communication via transmission or reception, but nottransmission and reception simultaneously). In some examples half-duplexcommunications may be performed at a reduced peak rate. Other powerconservation techniques for UEs 115 include entering a power saving“deep sleep” mode when not engaging in active communications, oroperating over a limited bandwidth (e.g., according to narrowbandcommunications). In some cases, UEs 115 may be designed to supportcritical functions (e.g., mission critical functions), and wirelesscommunications system 100 may be configured to provide ultra-reliablecommunications for these functions.

In some cases, a UE 115 may also be able to communicate directly withother UEs 115 (e.g., using a peer-to-peer (P2P) or device-to-device(D2D) protocol). One or more of a group of UEs 115 utilizing D2Dcommunications may be within the geographic coverage area 110 of a basestation 105. Other UEs 115 in such a group may be outside the geographiccoverage area 110 of a base station 105 or be otherwise unable toreceive transmissions from a base station 105. In some cases, groups ofUEs 115 communicating via D2D communications may utilize a one-to-many(1:M) system in which each UE 115 transmits to every other UE 115 in thegroup. In some cases, a base station 105 facilitates the scheduling ofresources for D2D communications. In other cases, D2D communications arecarried out between UEs 115 without the involvement of a base station105.

Base stations 105 may communicate with the core network 130 and with oneanother. For example, base stations 105 may interface with the corenetwork 130 through backhaul links 132 (e.g., via an S1 or otherinterface). Base stations 105 may communicate with one another overbackhaul links 134 (e.g., via an X2 or other interface) either directly(e.g., directly between base stations 105) or indirectly (e.g., via corenetwork 130).

The core network 130 may provide user authentication, accessauthorization, tracking, Internet Protocol (IP) connectivity, and otheraccess, routing, or mobility functions. The core network 130 may be anevolved packet core (EPC), which may include at least one mobilitymanagement entity (MME), at least one serving gateway (S-GW), and atleast one Packet Data Network (PDN) gateway (P-GW). The MME may managenon-access stratum (e.g., control plane) functions such as mobility,authentication, and bearer management for UEs 115 served by basestations 105 associated with the EPC. User IP packets may be transferredthrough the S-GW, which itself may be connected to the P-GW. The P-GWmay provide IP address allocation as well as other functions. The P-GWmay be connected to the network operators IP services. The networkoperators IP services may include access to the Internet, Intranet(s),an IP Multimedia Subsystem (IMS), or a Packet-Switched (PS) StreamingService.

At least some of the network devices, such as a base station 105, mayinclude subcomponents such as an access network entity, which may be anexample of an access node controller (ANC). Each access network entitymay communicate with UEs 115 through a number of other access networktransmission entities, which may be referred to as a radio head, a smartradio head, or a transmission/reception point (TRP). In someconfigurations, various functions of each access network entity or basestation 105 may be distributed across various network devices (e.g.,radio heads and access network controllers) or consolidated into asingle network device (e.g., a base station 105).

Wireless communications system 100 may operate using one or morefrequency bands, typically in the range of 300 megahertz (MHz) to 300gigahertz (GHz). Generally, the region from 300 MHz to 3 GHz is known asthe ultra-high frequency (UHF) region or decimeter band, since thewavelengths range from approximately one decimeter to one meter inlength. UHF waves may be blocked or redirected by buildings andenvironmental features. However, the waves may penetrate structuressufficiently for a macro cell to provide service to UEs 115 locatedindoors. Transmission of UHF waves may be associated with smallerantennas and shorter range (e.g., less than 100 km) compared totransmission using the smaller frequencies and longer waves of the highfrequency (HF) or very high frequency (VHF) portion of the spectrumbelow 300 MHz.

Wireless communications system 100 may also operate in a super highfrequency (SHF) region using frequency bands from 3 GHz to 30 GHz, alsoknown as the centimeter band. The SHF region includes bands such as the5 GHz industrial, scientific, and medical (ISM) bands, which may be usedopportunistically by devices that can tolerate interference from otherusers.

Wireless communications system 100 may also operate in an extremely highfrequency (EHF) region of the spectrum (e.g., from 25 GHz to 300 GHz),also known as the millimeter band. In some examples, wirelesscommunications system 100 may support millimeter wave (mmW)communications between UEs 115 and base stations 105, and EHF antennasof the respective devices may be even smaller and more closely spacedthan UHF antennas. In some cases, this may facilitate use of antennaarrays within a UE 115. However, the propagation of EHF transmissionsmay be subject to even greater atmospheric attenuation and shorter rangethan SHF or UHF transmissions. Techniques disclosed herein may beemployed across transmissions that use one or more different frequencyregions, and designated use of bands across these frequency regions maydiffer by country or regulating body.

In some cases, wireless communications system 100 may utilize bothlicensed and unlicensed radio frequency spectrum bands. For example,wireless communications system 100 may employ License Assisted Access(LAA), LTE-Unlicensed (LTE-U) radio access technology, or NR technologyin an unlicensed band such as the 5 GHz ISM band. When operating inunlicensed radio frequency spectrum bands, wireless devices such as basestations 105 and UEs 115 may employ listen-before-talk (LBT) proceduresto ensure a frequency channel is clear before transmitting data. In somecases, operations in unlicensed bands may be based on a CA configurationin conjunction with CCs operating in a licensed band (e.g., LAA).Operations in unlicensed spectrum may include downlink transmissions,uplink transmissions, peer-to-peer transmissions, or a combination ofthese. Duplexing in unlicensed spectrum may be based on frequencydivision duplexing (FDD), time division duplexing (TDD), or acombination of both.

In some examples, base station 105 or UE 115 may be equipped withmultiple antennas, which may be used to employ techniques such astransmit diversity, receive diversity, multiple-input multiple-output(MIMO) communications, or beamforming. For example, wirelesscommunications system 100 may use a transmission scheme between atransmitting device (e.g., a base station 105) and a receiving device(e.g., a UE 115), where the transmitting device is equipped withmultiple antennas and the receiving devices are equipped with one ormore antennas. MIMO communications may employ multipath signalpropagation to increase the spectral efficiency by transmitting orreceiving multiple signals via different spatial layers, which may bereferred to as spatial multiplexing. The multiple signals may, forexample, be transmitted by the transmitting device via differentantennas or different combinations of antennas. Likewise, the multiplesignals may be received by the receiving device via different antennasor different combinations of antennas. Each of the multiple signals maybe referred to as a separate spatial stream and may carry bitsassociated with the same data stream (e.g., the same codeword) ordifferent data streams. Different spatial layers may be associated withdifferent antenna ports used for channel measurement and reporting. MIMOtechniques include single-user MIMO (SU-MIMO) where multiple spatiallayers are transmitted to the same receiving device, and multiple-userMIMO (MU-MIMO) where multiple spatial layers are transmitted to multipledevices.

Beamforming, which may also be referred to as spatial filtering,directional transmission, or directional reception, is a signalprocessing technique that may be used at a transmitting device or areceiving device (e.g., a base station 105 or a UE 115) to shape orsteer an antenna beam (e.g., a transmit beam or receive beam) along aspatial path between the transmitting device and the receiving device.Beamforming may be achieved by combining the signals communicated viaantenna elements of an antenna array such that signals propagating atparticular orientations with respect to an antenna array experienceconstructive interference while others experience destructiveinterference. The adjustment of signals communicated via the antennaelements may include a transmitting device or a receiving deviceapplying certain amplitude and phase offsets to signals carried via eachof the antenna elements associated with the device. The adjustmentsassociated with each of the antenna elements may be defined by abeamforming weight set associated with a particular orientation (e.g.,with respect to the antenna array of the transmitting device orreceiving device, or with respect to some other orientation).

In one example, a base station 105 may use multiple antennas or antennaarrays to conduct beamforming operations for directional communicationswith a UE 115. For instance, some signals (e.g., synchronizationsignals, reference signals, beam selection signals, or other controlsignals) may be transmitted by a base station 105 multiple times indifferent directions, which may include a signal being transmittedaccording to different beamforming weight sets associated with differentdirections of transmission. Transmissions in different beam directionsmay be used to identify (e.g., by the base station 105 or a receivingdevice, such as a UE 115) a beam direction for subsequent transmissionand/or reception by the base station 105. Some signals, such as datasignals associated with a particular receiving device, may betransmitted by a base station 105 in a single beam direction (e.g., adirection associated with the receiving device, such as a UE 115). Insome examples, the beam direction associated with transmissions along asingle beam direction may be determined based at least in in part on asignal that was transmitted in different beam directions. For example, aUE 115 may receive one or more of the signals transmitted by the basestation 105 in different directions, and the UE 115 may report to thebase station 105 an indication of the signal it received with a highestsignal quality, or an otherwise acceptable signal quality. Althoughthese techniques are described with reference to signals transmitted inone or more directions by a base station 105, a UE 115 may employsimilar techniques for transmitting signals multiple times in differentdirections (e.g., for identifying a beam direction for subsequenttransmission or reception by the UE 115) or transmitting a signal in asingle direction (e.g., for transmitting data to a receiving device).

A receiving device (e.g., a UE 115, which may be an example of a mmWreceiving device) may try multiple receive beams when receiving varioussignals from the base station 105, such as synchronization signals,reference signals, beam selection signals, or other control signals. Forexample, a receiving device may try multiple receive directions byreceiving via different antenna subarrays, by processing receivedsignals according to different antenna subarrays, by receiving accordingto different receive beamforming weight sets applied to signals receivedat a plurality of antenna elements of an antenna array, or by processingreceived signals according to different receive beamforming weight setsapplied to signals received at a plurality of antenna elements of anantenna array, any of which may be referred to as “listening” accordingto different receive beams or receive directions. In some examples areceiving device may use a single receive beam to receive along a singlebeam direction (e.g., when receiving a data signal). The single receivebeam may be aligned in a beam direction determined based at least inpart on listening according to different receive beam directions (e.g.,a beam direction determined to have a highest signal strength, highestsignal-to-noise ratio, or otherwise acceptable signal quality based atleast in part on listening according to multiple beam directions).

In some cases, the antennas of a base station 105 or UE 115 may belocated within one or more antenna arrays, which may support MIMOoperations, or transmit or receive beamforming. For example, one or morebase station antennas or antenna arrays may be co-located at an antennaassembly, such as an antenna tower. In some cases, antennas or antennaarrays associated with a base station 105 may be located in diversegeographic locations. A base station 105 may have an antenna array witha number of rows and columns of antenna ports that the base station 105may use to support beamforming of communications with a UE 115.Likewise, a UE 115 may have one or more antenna arrays that may supportvarious MIMO or beamforming operations.

In some cases, wireless communications system 100 may be a packet-basednetwork that operates according to a layered protocol stack. In the userplane, communications at the bearer or Packet Data Convergence Protocol(PDCP) layer may be IP-based. A Radio Link Control (RLC) layer may, insome cases, perform packet segmentation and reassembly to communicateover logical channels. A Medium Access Control (MAC) layer may performpriority handling and multiplexing of logical channels into transportchannels. The MAC layer may also use hybrid automatic repeat request(HARQ) to provide retransmission at the MAC layer to improve linkefficiency. In the control plane, the Radio Resource Control (RRC)protocol layer may provide establishment, configuration, and maintenanceof an RRC connection between a UE 115 and a base station 105 or corenetwork 130 supporting radio bearers for user plane data. At thePhysical (PHY) layer, transport channels may be mapped to physicalchannels.

In some cases, UEs 115 and base stations 105 may support retransmissionsof data to increase the likelihood that data is received successfully.HARQ feedback is one technique of increasing the likelihood that data isreceived correctly over a communication link 125. HARQ may include acombination of error detection (e.g., using a cyclic redundancy check(CRC)), forward error correction (FEC), and retransmission (e.g.,automatic repeat request (ARQ)). HARQ may improve throughput at the MAClayer in poor radio conditions (e.g., signal-to-noise conditions). Insome cases, a wireless device may support same-slot HARQ feedback, wherethe device may provide HARQ feedback in a specific slot for datareceived in a previous symbol in the slot. In other cases, the devicemay provide HARQ feedback in a subsequent slot, or according to someother time interval.

Time intervals in LTE or NR may be expressed in multiples of a basictime unit, which may, for example, refer to a sampling period ofT_(s)=1/30,720,000 seconds. Time intervals of a communications resourcemay be organized according to radio frames each having a duration of 10milliseconds (ms), where the frame period may be expressed asT_(f)=307,200 T_(s). The radio frames may be identified by a systemframe number (SFN) ranging from 0 to 1023. Each frame may include 10subframes numbered from 0 to 9, and each subframe may have a duration of1 ms. A subframe may be further divided into 2 slots each having aduration of 0.5 ms, and each slot may contain 6 or 7 modulation symbolperiods (e.g., depending on the length of the cyclic prefix prepended toeach symbol period). Excluding the cyclic prefix, each symbol period maycontain 2048 sampling periods. In some cases, a subframe may be thesmallest scheduling unit of the wireless communications system 100 andmay be referred to as a transmission time interval (TTI). In othercases, a smallest scheduling unit of the wireless communications system100 may be shorter than a subframe or may be dynamically selected (e.g.,in bursts of shortened TTIs (sTTIs) or in selected component carriersusing sTTIs).

In some wireless communications systems, a slot may further be dividedinto multiple mini-slots containing one or more symbols. In someinstances, a symbol of a mini-slot or a mini-slot may be the smallestunit of scheduling. Each symbol may vary in duration depending on thesubcarrier spacing or frequency band of operation, for example. Further,some wireless communications systems may implement slot aggregation inwhich multiple slots or mini-slots are aggregated together and used forcommunication between a UE 115 and a base station 105.

The term “carrier” refers to a set of radio frequency spectrum resourceshaving a defined physical layer structure for supporting communicationsover a communication link 125. For example, a carrier of a communicationlink 125 may include a portion of a radio frequency spectrum band thatis operated according to physical layer channels for a given radioaccess technology. Each physical layer channel may carry user data,control information, or other signaling. A carrier may be associatedwith a pre-defined frequency channel (e.g., an E-UTRA absolute radiofrequency channel number (EARFCN)) and may be positioned according to achannel raster for discovery by UEs 115. Carriers may be downlink oruplink (e.g., in an FDD mode), or be configured to carry downlink anduplink communications (e.g., in a TDD mode). In some examples, signalwaveforms transmitted over a carrier may be made up of multiplesub-carriers (e.g., using multi-carrier modulation (MCM) techniques suchas orthogonal frequency-division multiplexing (OFDM) or DFT-s-OFDM).

The organizational structure of the carriers may be different fordifferent radio access technologies (e.g., LTE, LTE-A, LTE-A Pro, NR,etc.). For example, communications over a carrier may be organizedaccording to TTIs or slots, each of which may include user data as wellas control information or signaling to support decoding the user data. Acarrier may also include dedicated acquisition signaling (e.g.,synchronization signals or system information, etc.) and controlsignaling that coordinates operation for the carrier. In some examples(e.g., in a carrier aggregation configuration), a carrier may also haveacquisition signaling or control signaling that coordinates operationsfor other carriers.

Physical channels may be multiplexed on a carrier according to varioustechniques. A physical control channel and a physical data channel maybe multiplexed on a downlink carrier, for example, using time divisionmultiplexing (TDM) techniques, frequency division multiplexing (FDM)techniques, or hybrid TDM-FDM techniques. In some examples, controlinformation transmitted in a physical control channel may be distributedbetween different control regions in a cascaded manner (e.g., between acommon control region or common search space and one or more UE-specificcontrol regions or UE-specific search spaces).

A carrier may be associated with a particular bandwidth of the radiofrequency spectrum, and in some examples the carrier bandwidth may bereferred to as a “system bandwidth” of the carrier or the wirelesscommunications system 100. For example, the carrier bandwidth may be oneof a number of predetermined bandwidths for carriers of a particularradio access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 MHz). Insome examples, each served UE 115 may be configured for operating overportions or all of the carrier bandwidth. In other examples, some UEs115 may be configured for operation using a narrowband protocol typethat is associated with a predefined portion or range (e.g., set ofsubcarriers or RBs) within a carrier (e.g., “in-band” deployment of anarrowband protocol type).

In a system employing MCM techniques, a resource element may consist ofone symbol period (e.g., a duration of one modulation symbol) and onesubcarrier, where the symbol period and subcarrier spacing are inverselyrelated. The number of bits carried by each resource element may dependon the modulation scheme (e.g., the order of the modulation scheme).Thus, the more resource elements that a UE 115 receives and the higherthe order of the modulation scheme, the higher the data rate may be forthe UE 115. In MIMO systems, a wireless communications resource mayrefer to a combination of a radio frequency spectrum resource, a timeresource, and a spatial resource (e.g., spatial layers), and the use ofmultiple spatial layers may further increase the data rate forcommunications with a UE 115.

Devices of the wireless communications system 100 (e.g., base stations105 or UEs 115) may have a hardware configuration that supportscommunications over a particular carrier bandwidth or may beconfigurable to support communications over one of a set of carrierbandwidths. In some examples, the wireless communications system 100 mayinclude base stations 105 and/or UEs 115 that can support simultaneouscommunications via carriers associated with more than one differentcarrier bandwidth.

Wireless communications system 100 may support communication with a UE115 on multiple cells or carriers, a feature which may be referred to ascarrier aggregation (CA) or multi-carrier operation. A UE 115 may beconfigured with multiple downlink CCs and one or more uplink CCsaccording to a carrier aggregation configuration. CA may be used withboth FDD and TDD component carriers.

In some cases, wireless communications system 100 may utilize enhancedcomponent carriers (eCCs). An eCC may be characterized by one or morefeatures including wider carrier or frequency channel bandwidth, shortersymbol duration, shorter TTI duration, or modified control channelconfiguration. In some cases, an eCC may be associated with a carrieraggregation configuration or a dual connectivity configuration (e.g.,when multiple serving cells have a suboptimal or non-ideal backhaullink). An eCC may also be configured for use in unlicensed spectrum orshared spectrum (e.g., where more than one operator is allowed to usethe spectrum). An eCC characterized by wide carrier bandwidth mayinclude one or more segments that may be utilized by UEs 115 that arenot capable of monitoring the whole carrier bandwidth or are otherwiseconfigured to use a limited carrier bandwidth (e.g., to conserve power).

In some cases, an eCC may utilize a different symbol duration than otherCCs, which may include use of a reduced symbol duration as compared withsymbol durations of the other CCs. A shorter symbol duration may beassociated with increased spacing between adjacent subcarriers. Adevice, such as a UE 115 or base station 105, utilizing eCCs maytransmit wideband signals (e.g., according to frequency channel orcarrier bandwidths of 20, 40, 60, 80 MHz, etc.) at reduced symboldurations (e.g., 16.67 μs). A TTI in eCC may consist of one or multiplesymbol periods. In some cases, the TTI duration (that is, the number ofsymbol periods in a TTI) may be variable.

Wireless communications systems such as an NR system may utilize anycombination of licensed, shared, and unlicensed spectrum bands, amongothers. The flexibility of eCC symbol duration and subcarrier spacingmay allow for the use of eCC across multiple spectrums. In someexamples, NR shared spectrum may increase spectrum utilization andspectral efficiency, specifically through dynamic vertical (e.g., acrossfrequency) and horizontal (e.g., across time) sharing of resources.

PUCCH may be mapped to a control channel defined by a code and twoconsecutive resource blocks. Uplink control signaling may depend on thepresence of timing synchronization for a cell. PUCCH resources forscheduling request (SR) and channel quality indicator (CQI) reportingmay be assigned (and revoked) through RRC signaling. In some cases,resources for SR may be assigned after acquiring synchronization througha random access procedure (e.g., using a random access channel (RACH)).In other cases, an SR may not be assigned to a UE 115 through the RACH(i.e., synchronized UEs may or may not have a dedicated SR channel).PUCCH resources for SR and CQI may be lost when the UE 115 is no longersynchronized.

Wireless communications system 100 may support the use of randomizedshifts of a base sequence used for transmitting uplink controlinformation, which may lead to reduced interference between differentUEs 115. For example, a UE 115 may identify a base sequence that is usedfor the transmission of an uplink control message. The UE 115 may alsoreceive signaling that is indicative of a UE-specific initial shift thatmay be applied to the identified base sequence. In some cases, thesignaling may be explicit (e.g., using a number of bits in a receivedcontrol message) or may be implicit based on a mapping of a CCE index.In other examples, there may be a combination of explicit and implicitmapping used for the indication of the randomized initial shift. Afterdetermining one or more shifted sequences based on the UE-specificinitial shift and the base sequence, the UE 115 may select a shiftedsequence based on a payload of the uplink control message. For example,different shifted sequences may be used for respective transmissions ofscheduling requests, 1-bit ACKs, 2-bit ACKs, and the like. The UE 115may transmit the uplink control message based on the selected shiftedsequence to a base station 105, and different UEs 115 may likewise usedifferent initial shifts for their own respective transmissions to thebase station 105.

FIGS. 2A and 2B illustrate examples of hypotheses 200 and UE-specificshifts 201, respectively, in a system that support UE shiftrandomization for uplink control channel transmission in accordance withvarious aspects of the present disclosure. In some examples, hypotheses200 and UE-specific shifts 201 may be implemented in accordance withaspects of wireless communications system 100. For example, a UE 115 maytransmit uplink control messages using a randomized initial shift of thesequence that makes up the control information. Such techniques may beused to randomize interference between UEs 115 that share the sameresources (e.g., are multiplexed on the same RB).

In some examples, uplink control information may utilize asequence-based design (e.g., uplink control information may be signaledas a particular sequence), and different formats of a PUCCH may be usedfor different purposes. For example, PUCCH Format 0 may be associatedwith a short PUCCH (sPUCCH) transmission, which may include uplinkcontrol information with a certain number of bits (e.g., 1 or 2 bits).In such cases, using a base sequence (e.g., having a length of 12), a UE115 may be assigned an initial shift, and the UE 115 may then deriveother shifts based on the initial shift. In some examples, and asdescribed below, the derivation of the other shifts may be based on theuplink control information (e.g., 1-bit ACK, 2-bit ACK, SR), andshifting the base sequence may thus be based on the initial shift andthe other shifts that are derived from the uplink control information.As an example, a base sequence with a length of 12 may be transmitted ina single resource bandwidth, and using cyclic shifts (e.g., in the timedomain), there may different shifts of the base sequence that may bederived.

A UE 115 may be assigned an initial shift. The UE 115 may determine theinitial shift based on a UE-specific hopping pattern (e.g., S0′) and acell-specific hopping pattern. In some examples, a UE 115 may determinea first shift S0 using the equation S0=(S0′+Scell)mod12. In some cases,Scell may be predefined and may be a function of a cell ID and S0′ maybe provided to the UE 115 by the base station 105.

As illustrated in FIG. 2A, different hypothesis may be used withdifferent shifts 205. For instance, for a first hypothesis 200-a usedfor the transmission of an SR, there may be twelve possible locationsfor a shift 205. Accordingly, a transmission of an SR (which maycomprise only a single bit) by a UE 115 may include only one shift 205(e.g., only S0).

In another example, such as hypothesis 200-b for a transmission of a1-bit ACK, there may be a total of two shifts with a certain shiftdistance between shifts 205. As illustrated in the clock representationof hypothesis 200-b, a location of a shift 205 within a hypothesis 200may correspond to a value of the shift 205, and a shift distance maycorrespond to a difference between respective shift values. As anillustrative example, a first shift 205-a may correspond to a shiftvalue of 0 and a second shift 205-b may correspond to a shift value of6. In some examples, the two shifts may be based on a value of the ACKbit (e.g., 1 or 0), where each value of the ACK bit may correspond to adifferent shift. In some cases, there may be twelve possible locationsfor the first shift 205-a, and the second shift 205-b may be separatedby a distance of six shifts 205. For example, when a shift distanceequals six, there may be a first shift, S0 (corresponding to shift205-a), and a second shift, S1 (corresponding to shift 205-b), which maybe calculated using the equation S1=(S0+6)mod12).

In yet another example, in a third hypothesis 200-c for a 2-bit ACK,there may be a total of four shifts with a certain shift distancebetween each shift, where different shifts may correspond to differentvalues in the clock representation of hypothesis 200-c. For instance,for a shift distance of three shifts, the UE 115 may use a first shiftS0 (e.g., having a value of 0), a second shift, S1, calculated usingS1=(S0+3)mod12 (e.g., having a value of 3), a third shift, S2,calculated using (S0+6)mod12 (e.g., having a value of 6), or a fourthshift, S3, calculated using S3=(S0+9)mod12 (e.g., having a value of 9.In some examples, the four shifts may each be associated with adifferent value of the 2-bit ACK (e.g., {0,0}, {0,1}, {1,0}, and {1,1}).In other words, each 2-bit ACK value pair may correspond to a differentshift. For instance, a 2-bit ACK having a value of {0, 0} may correspondto the first shift, while a 2-bit ACK having a value of {1,1} maycorrespond to the fourth shift.

As illustrated in FIG. 2B, different UEs 115 may be separated usingdifferent shifts. For example, there may be a total of 12 shifts percell RB. Accordingly, for SR transmissions, there may be up to 12 UEs115 multiplexed per RB, each UE 115 with one shift. For 1-bit ACKtransmissions, for example, there may be up to 6 UEs 115 multiplexed perRB, each UE 115 with 2 shifts. For instance, as shown in UE-specificshift 201-a, a first UE 115 may use a first shift 210-a for NACKtransmissions and also use a second shift 210-b for ACK transmissions.Likewise, a second UE 115 may use a first shift 215-a for NACKtransmissions and also use a second shift 215-b for ACK transmissions.Additionally or alternatively, and as shown in UE-specific shifts 201-b,for 2-bit ACK transmissions, there may be up to 3 UEs 115 multiplexedper RB, each UE 115 with 4 shifts 210, 215. In any event, there may be amapping between different shifts used by UEs 115 for the transmission ofACK and NACK. In some cases, the mapping may be predetermined.

In some cases, there may be interference from the different UEs 115 thatare multiplexed on a same RB. For example, in cases where there is aphysical downlink shared channel (PDSCH) decoding rate of 90 percent fora first transmission, 90 percent of the ACK channel may be used for anACK hypothesis (e.g., across all UEs 115). If two UEs 115 use the sameor similar shifts, then the respective UEs 115 may experienceinterference from each other.

Accordingly, techniques may be used to mitigate interference bydifferent UEs 115. In some cases, there may a randomized hypothesismapping used, which may randomize interference. Alternatively, and asdescribed herein, there may a randomization of shift sequences used togenerate an uplink control message, which may also randomize theinterference. In some examples, a randomized hypothesis mapping mayintroduce additional pseudo-random sequences, potentially resulting ingreater complexity than the use of a random initial shift.

The initial shift may be UE-specific and may be indicated using varioustechniques. For instance, the initial shift may be explicitly indicatedor implicitly mapped, or a combination thereof. As an example, there maybe an explicit indication using a certain number of bits in a downlinkcontrol message. In such cases, ACK/NACK resource indicator or ARI bitsmay be used for the explicit indication of the random initial shift. Insuch cases, there may be Y configured resources (e.g., configured usingRRC signaling) for a UE 115. As a result, X ARI bits may be used toindicate one or more of the resources to use for PUCCH format 0, where2^(X)≥Y. As an illustrative example, X=2, and Y=4 resources, and an ARIbit may indicate one of the 4 resources configured by the base station105. In some cases, multiple resources may include different shifts withother parameters being the same. Accordingly, the ARI bits may indicatedifferent initial shifts for different transmissions (e.g., onrespective resources). In such cases, different initial shifts may beindicated by different ARI bit values.

Additionally or alternatively, there may be an implicit mapping based ona CCE index of a downlink grant control message (e.g., received by theUE 115 on a PDCCH). In such cases, there may be an implicit mappingwhere there are no AM bits included in DCI, and the UE 115 may insteadrely on the CCE index to derive an RB index and the shift index. Foreach transmission, a PDCCH may be randomized, therefore the initialshifts may also be randomized.

In another example, there may be a combination of explicit and implicitmapping. For example, when 2^(X)<Y, X ARI bits may not be sufficient toselect a particular resource from the Y resources. For instance, X=2 andY=8 resources, the 2 ARI bits may not be sufficient to indicate aparticular resource. As a result, a UE 115 may use X ARI bits to selecta subset of resources (e.g., with cell (2^(X)/Y) resources) and may thenuse the CCE index to select one of the resources in the subset. Forinstance, each subset may have two resources, and the CCE index may beused to identify a particular resource. In other words, subsets ofresources may be implicitly indicated and resources within the subsetsmay be implicitly mapped. In some cases, different subsets maycorrespond to the same or different initial shift. Additionally oralternatively, different resources within the same subset may correspondto the same or different initial shift. As such, randomized shifts maybe associated with a resource allocation based on ARI bits, a CCE index,or a combination thereof, and the randomization may be achieved throughthe selection of a resource within a subset of resources.

Using the techniques described herein, the use of the UE-specificinitial shift may enable different shifts to be used for differenthypothesis 200 and used by different UEs 115. For instance, whentransmitting using the second hypothesis 200-b, a given UE 115 may use aparticular shift for the transmission of ACK/NACK for 1-bit ACKs,whereas another UE 115 may use a different shift, thereby randomizinginterference for both UEs 115. Likewise, with the UE-specific shifts201, the transmissions of ACK/NACK (or scheduling requests) may alsoinclude randomized sequences based on the initial shift used by each UE115. Such techniques may enable a greater probability that interferencemay be randomized between respective UEs 115 (e.g., UEs 115 that aremultiplexed on the same resources).

FIG. 3 illustrates an example of a process flow 300 in a system thatsupports UE shift randomization for uplink control channel transmissionin accordance with various aspects of the present disclosure. In someexamples, process flow 300 may implement aspects of wirelesscommunications system 100. For instance, process flow 300 includes a UE115-a and base station 105-a, which may be examples of the correspondingdevices described with reference to FIG. 1. Process flow 300 mayillustrate the randomization of sequences to efficiently reduceinterference between wireless devices transmitting on resources within acell.

At 305, UE 115-a may identify a base sequence for transmission in anuplink control message. At 310, base station 105-a may transmit, and UE115-a may receive, signaling indicative of a UE-specific initial shiftto be applied to (e.g., utilized with) the base sequence. In some cases,base station 105-a may transmit signaling to different UEs 115 (e.g.,including UE 115-a), and the signaling may be indicative of differentUE-specific initial shifts to be applied to the base sequence byrespective UEs 115 such that interference between transmissions ofuplink control messages is randomized. In some cases, shifted sequencesused when generating an uplink control payload may be randomized forrespective transmissions, and different transmissions by respective UEs115 may use different shifts. In such cases, sequences may beefficiently randomized with minimal complexity.

For example, UE 115-a may receive an explicit indication of theUE-specific initial shift. In some examples, the explicit indication isincluded within ARI bits of a downlink DCI message transmitted by basestation 105-a. A number of the ARI bits may be sufficiently large suchthat two raised to the number of the ARI bits is greater than or equalto a number of resources configured for the uplink control message. Thatis, 2^(X)≥Y, as described above.

In some examples, receiving the signaling indicative of the UE-specificinitial shift includes receiving a downlink grant control message havinga CCE index from which the UE-specific initial shift is determined. Insuch cases, an RB index and a shift index for the UE-specific initialshift may be derived based on the CCE index of the downlink grantcontrol message.

Additionally or alternatively, receiving the signaling includesreceiving an explicit indication of a subset of resources configured forthe uplink control message and receiving a downlink grant controlmessage having a CCE index. Accordingly, UE 115-a may derive an RB indexand shift index for the UE-specific initial shift based at least in parton the CCE index as applied to the subset of resources. In someexamples, the explicit indication is included within ARI bits of a DCImessage. In some cases, a number of the ARI bits is such that two raisedto the number of the ARI bits is less than a number of the resourcesconfigured for the uplink control message. That is, 2^(X)<Y, asdescribed above. In some examples, at 315, UE 115-a may determine theUE-specific initial shift based on the signaling. At 320, UE 115-a maydetermine one or more shifted sequences based on the UE-specific initialshift and the base sequence. In some examples, UE 115-a may determineinformation included in the uplink control message (e.g., a payloadincluding a 1-bit ACK, 2-bit ACK, an SR, etc.), and may determine ashifted sequence based on the information included in the uplink controlmessage. For example, as mentioned above, PUCCH Format 0 may beassociated with sPUCCH transmissions, which may include uplink controlinformation (e.g., SR, ACK/NACK, etc.) with 1 or 2 bits. UE 115-a maythus determine the number of bits in the uplink control information tobe sent using sPUCCH, and the shifted sequence may be based on thenumber of bits of the payload as described with reference to FIGS. 2Aand 2B. Accordingly, UE 115-a may determine the shifted sequence basedon the UE-specific initial shift, the base sequence, and the number ofbits of uplink control information to be set using the uplink controlmessage. In some examples, at 325, UE 115-a may select a shiftedsequence from one or more shifted sequences based at least in part onthe payload of the uplink control message. In some examples, selectingthe shifted sequence from the one or more shifted sequences based on thepayload of the uplink control message may include identifying that thepayload of the uplink control message is one of an SR, a 1-bit ACK, or a2-bit ACK, and then selecting a shifted sequence based at least in parton the identified payload. In some cases, UE 115-a may randomize theselecting of the shifted sequence from the one or more shiftedsequences.

At 330, UE 115-a may transmit, and base station 105-a may receive,uplink control information in the uplink control message based on theshifted sequence. For example, the uplink control message may comprisethe shifted sequence that is mapped to physical resources (e.g., REs)for transmission to base station 105-a. In some cases, the uplinkcontrol message may be formatted as an sPUCCH message having one or twobits of uplink control information.

FIG. 4 shows a block diagram 400 of a wireless device 405 that supportsUE shift randomization for uplink control channel transmission inaccordance with aspects of the present disclosure. Wireless device 405may be an example of aspects of a UE 115 as described herein. Wirelessdevice 405 may include receiver 410, UE communications manager 415, andtransmitter 420. Wireless device 405 may also include a processor. Eachof these components may be in communication with one another (e.g., viaone or more buses).

Receiver 410 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to UE shiftrandomization for uplink control channel transmission, etc.).Information may be passed on to other components of the device. Thereceiver 410 may be an example of aspects of the transceiver 735described with reference to FIG. 7. The receiver 410 may utilize asingle antenna or a set of antennas.

UE communications manager 415 may be an example of aspects of the UEcommunications manager 715 described with reference to FIG. 7. UEcommunications manager 415 and/or at least some of its varioussub-components may be implemented in hardware, software executed by aprocessor, firmware, or any combination thereof. If implemented insoftware executed by a processor, the functions of the UE communicationsmanager 415 and/or at least some of its various sub-components may beexecuted by a general-purpose processor, a digital signal processor(DSP), an application-specific integrated circuit (ASIC), afield-programmable gate array (FPGA) or other programmable logic device,discrete gate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described in thepresent disclosure.

The UE communications manager 415 and/or at least some of its varioussub-components may be physically located at various positions, includingbeing distributed such that portions of functions are implemented atdifferent physical locations by one or more physical devices. In someexamples, UE communications manager 415 and/or at least some of itsvarious sub-components may be a separate and distinct component inaccordance with various aspects of the present disclosure. In otherexamples, UE communications manager 415 and/or at least some of itsvarious sub-components may be combined with one or more other hardwarecomponents, including but not limited to an I/O component, atransceiver, a network server, another computing device, one or moreother components described in the present disclosure, or a combinationthereof in accordance with various aspects of the present disclosure.

UE communications manager 415 may identify a base sequence fortransmission of an uplink control message, receive signaling indicativeof a UE-specific initial shift to be used with the base sequence, anddetermine the UE-specific initial shift based on the signaling. In somecases, UE communications manager 415 may determine uplink controlinformation based for the uplink control message, determine a shiftedsequence of the base sequence based on the UE-specific initial shift andthe uplink control information, and transmit the uplink controlinformation in the uplink control message, where the uplink controlinformation is based on the shifted sequence.

Transmitter 420 may transmit signals generated by other components ofthe device. In some examples, the transmitter 420 may be collocated witha receiver 410 in a transceiver module. For example, the transmitter 420may be an example of aspects of the transceiver 735 described withreference to FIG. 7. The transmitter 420 may utilize a single antenna ora set of antennas.

FIG. 5 shows a block diagram 500 of a wireless device 505 that supportsUE shift randomization for uplink control channel transmission inaccordance with aspects of the present disclosure. Wireless device 505may be an example of aspects of a wireless device 405 or a UE 115 asdescribed with reference to FIG. 4. Wireless device 505 may includereceiver 510, UE communications manager 515, and transmitter 520.Wireless device 505 may also include a processor. Each of thesecomponents may be in communication with one another (e.g., via one ormore buses).

Receiver 510 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to UE shiftrandomization for uplink control channel transmission, etc.).Information may be passed on to other components of the device. Thereceiver 510 may be an example of aspects of the transceiver 735described with reference to FIG. 7. The receiver 510 may utilize asingle antenna or a set of antennas.

UE communications manager 515 may be an example of aspects of the UEcommunications manager 715 described with reference to FIG. 7. UEcommunications manager 515 may also include sequence manager 525,randomized shift component 530, and control message transmissioncomponent 535.

Sequence manager 525 may identify a base sequence for transmission in anuplink control message, determine one or more shifted sequences based onthe UE-specific initial shift and the base sequence, and select ashifted sequence from the one or more shifted sequences based on apayload of the uplink control message. In some examples, sequencemanager 525 may select the shifted sequence based on the identifiedpayload. In some examples, sequence manager 525 may determine a shiftedsequence of the base sequence based on the UE-specific initial shift andthe uplink control information. In some examples, sequence manager 525may randomize the selecting of the shifted sequence from the one or moreshifted sequences. In some cases, selecting the shifted sequence fromthe one or more shifted sequences based on the payload of the uplinkcontrol message includes identifying that the payload of the uplinkcontrol message is one of an SR, a one-bit ACK, or a two-bit ACK.

Randomized shift component 530 may receive signaling that indicates(e.g., is indicative of) a UE-specific initial shift to be applied tothe base sequence and determine the UE-specific initial shift based onthe signaling. In some cases, receiving signaling indicative of theUE-specific initial shift includes receiving an explicit indication ofthe UE-specific initial shift. In some cases, the explicit indication isincluded within ARI bits of a DCI message. In some cases, a number ofthe ARI bits is sufficiently large such that two raised to the number ofthe ARI bits is greater than a number of resources configured for theuplink control message.

In some cases, receiving signaling indicative of the UE-specific initialshift includes receiving a downlink grant control message having a CCEindex from which the UE-specific initial shift is derived. In somecases, determining the UE-specific initial shift includes deriving an RBindex and shift index for the UE-specific initial shift based on the CCEindex of the downlink grant control message. In some cases, receivingsignaling indicative of the UE-specific initial shift includes receivingan explicit indication of a subset of resources configured for theuplink control message. In some cases, the explicit indication isincluded within ARI bits of a DCI message. In some cases, a number ofthe ARI bits is such that two raised to the number of the ARI bits isless than a number of the resources configured for the uplink controlmessage.

Control message transmission component 535 may transmit the selectedshifted sequence in the uplink control message. In some examples,control message transmission component 535 may determine a number ofbits of uplink control information based on a payload of the uplinkcontrol message. In some examples, control message transmissioncomponent 535 may transmit the uplink control information in the uplinkcontrol message, wherein the uplink control message is based on theshifted sequence. In some cases, the uplink control message is formattedas an sPUCCH message having only one or two bits of uplink controlinformation.

Transmitter 520 may transmit signals generated by other components ofthe device. In some examples, the transmitter 520 may be collocated witha receiver 510 in a transceiver module. For example, the transmitter 520may be an example of aspects of the transceiver 735 described withreference to FIG. 7. The transmitter 520 may utilize a single antenna ora set of antennas.

FIG. 6 shows a block diagram 600 of a UE communications manager 615 thatsupports UE shift randomization for uplink control channel transmissionin accordance with aspects of the present disclosure. The UEcommunications manager 615 may be an example of aspects of a UEcommunications manager 415, a UE communications manager 515, or a UEcommunications manager 715 described with reference to FIGS. 4, 5, and7. The UE communications manager 615 may include sequence manager 620,randomized shift component 625, control message transmission component630, downlink grant manager 635, and index manager 640. Each of thesemodules may communicate, directly or indirectly, with one another (e.g.,via one or more buses).

Sequence manager 620 may identify a base sequence for transmission in anuplink control message, determine one or more shifted sequences based onthe UE-specific initial shift and the base sequence, select a shiftedsequence from the one or more shifted sequences based on a payload ofthe uplink control message, select the shifted sequence based on theidentified payload, and randomize the selecting of the shifted sequencefrom the one or more shifted sequences. In some examples, sequencemanager 620 may determine a shifted sequence based on the UE-specificinitial shift, a number of bits of the uplink control information, andthe base sequence.

In some examples, sequence manager 620 may determine the shiftedsequence based at least in part on a shift value that corresponds to thepayload the uplink control information, the shift value comprising avalue of 0 or 6. In some examples, sequence manager 620 may determinethe shifted sequence based at least in part on a shift value thatcorresponds to the payload the uplink control information, the shiftvalue comprising a value of 0, 3, 6, or 9. In some cases, selecting theshifted sequence from the one or more shifted sequences based on thepayload of the uplink control message includes identifying that thepayload of the uplink control message includes an SR, a one-bit ACK, atwo-bit ACK, or the like.

Randomized shift component 625 may receive signaling indicative of aUE-specific initial shift to be applied to the base sequence anddetermine the UE-specific initial shift based on the signaling. In somecases, receiving signaling indicative of the UE-specific initial shiftincludes receiving an explicit indication of the UE-specific initialshift. In some cases, the explicit indication is included within ARIbits of a DCI message. In some cases, a number of the ARI bits issufficiently large such that two raised to the number of the ARI bits isgreater than a number of resources configured for the uplink controlmessage.

In some cases, receiving signaling indicative of the UE-specific initialshift includes receiving a downlink grant control message having a CCEindex from which the UE-specific initial shift is derived. In somecases, determining the UE-specific initial shift includes deriving an RBindex and shift index for the UE-specific initial shift based on the CCEindex of the downlink grant control message. In some cases, receivingsignaling indicative of the UE-specific initial shift includes receivingan explicit indication of a subset of resources configured for theuplink control message. In some cases, the explicit indication isincluded within ARI bits of a DCI message. In some cases, a number ofthe ARI bits is such that two raised to the number of the ARI bits isless than a number of the resources configured for the uplink controlmessage.

Control message transmission component 630 may transmit the selectedshifted sequence in the uplink control message. In some examples,control message transmission component 630 may determine a number ofbits of uplink control information based on a payload of the uplinkcontrol message. In some examples, control message transmissioncomponent 630 may transmit the uplink control information in the uplinkcontrol message, wherein the uplink control message is based on theshifted sequence. In some examples, control message transmissioncomponent 630 may determine a size of acknowledgment information in theuplink control information. In some cases, the uplink control message isformatted as an sPUCCH message having only one or two bits of uplinkcontrol information.

Downlink grant manager 635 may receive a downlink grant control messagehaving a CCE index. Index manager 640 may derive an RB index and shiftindex for the UE-specific initial shift based on the CCE index asapplied to the subset of resources.

FIG. 7 shows a diagram of a system 700 including a device 705 thatsupports UE shift randomization for uplink control channel transmissionin accordance with aspects of the present disclosure. Device 705 may bean example of or include the components of wireless device 405, wirelessdevice 505, or a UE 115 as described herein, e.g., with reference toFIGS. 4 and 5. Device 705 may include components for bi-directionalvoice and data communications including components for transmitting andreceiving communications, including UE communications manager 715,processor 720, memory 725, software 730, transceiver 735, antenna 740,and I/O controller 745. These components may be in electroniccommunication via one or more buses (e.g., bus 710). Device 705 maycommunicate wirelessly with one or more base stations 105.

Processor 720 may include an intelligent hardware device, (e.g., ageneral-purpose processor, a DSP, a central processing unit (CPU), amicrocontroller, an ASIC, an FPGA, a programmable logic device, adiscrete gate or transistor logic component, a discrete hardwarecomponent, or any combination thereof). In some cases, processor 720 maybe configured to operate a memory array using a memory controller. Inother cases, a memory controller may be integrated into processor 720.Processor 720 may be configured to execute computer-readableinstructions stored in a memory to perform various functions (e.g.,functions or tasks supporting UE shift randomization for uplink controlchannel transmission).

Memory 725 may include random-access memory (RAM) and read-only memory(ROM). The memory 725 may store computer-readable, computer-executablesoftware 730 including instructions that, when executed, cause theprocessor to perform various functions described herein. In some cases,the memory 725 may contain, among other things, a basic input/outputsystem (BIOS) which may control basic hardware or software operationsuch as the interaction with peripheral components or devices.

Software 730 may include code to implement aspects of the presentdisclosure, including code to support UE shift randomization for uplinkcontrol channel transmission. Software 730 may be stored in anon-transitory computer-readable medium such as system memory or othermemory. In some cases, the software 730 may not be directly executableby the processor but may cause a computer (e.g., when compiled andexecuted) to perform functions described herein.

Transceiver 735 may communicate bi-directionally, via one or moreantennas, wired, or wireless links as described herein. For example, thetransceiver 735 may represent a wireless transceiver and may communicatebi-directionally with another wireless transceiver. The transceiver 735may also include a modem to modulate the packets and provide themodulated packets to the antennas for transmission, and to demodulatepackets received from the antennas. In some cases, the wireless devicemay include a single antenna 740. However, in some cases, the device mayhave more than one antenna 740, which may be capable of concurrentlytransmitting or receiving multiple wireless transmissions.

I/O controller 745 may manage input and output signals for device 705.I/O controller 745 may also manage peripherals not integrated intodevice 705. In some cases, I/O controller 745 may represent a physicalconnection or port to an external peripheral. In some cases, I/Ocontroller 745 may utilize an operating system such as iOS®, ANDROID®,MS-DOS®, MS-WINDOWS®, OS/2®, UNIX®, LINUX®, or another known operatingsystem. In other cases, I/O controller 745 may represent or interactwith a modem, a keyboard, a mouse, a touchscreen, or a similar device.In some cases, I/O controller 745 may be implemented as part of aprocessor. In some cases, a user may interact with device 705 via I/Ocontroller 745 or via hardware components controlled by I/O controller745.

FIG. 8 shows a block diagram 800 of a wireless device 805 that supportsUE shift randomization for uplink control channel transmission inaccordance with aspects of the present disclosure. Wireless device 805may be an example of aspects of a base station 105 as described herein.Wireless device 805 may include receiver 810, base stationcommunications manager 815, and transmitter 820. Wireless device 805 mayalso include a processor. Each of these components may be incommunication with one another (e.g., via one or more buses).

Receiver 810 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to UE shiftrandomization for uplink control channel transmission, etc.).Information may be passed on to other components of the device. Thereceiver 810 may be an example of aspects of the transceiver 1135described with reference to FIG. 11. The receiver 810 may utilize asingle antenna or a set of antennas.

Base station communications manager 815 may be an example of aspects ofthe base station communications manager 1115 described with reference toFIG. 11. Base station communications manager 815 and/or at least some ofits various sub-components may be implemented in hardware, softwareexecuted by a processor, firmware, or any combination thereof. Ifimplemented in software executed by a processor, the functions of thebase station communications manager 815 and/or at least some of itsvarious sub-components may be executed by a general-purpose processor, aDSP, an ASIC, an FPGA or other programmable logic device, discrete gateor transistor logic, discrete hardware components, or any combinationthereof designed to perform the functions described in the presentdisclosure.

The base station communications manager 815 and/or at least some of itsvarious sub-components may be physically located at various positions,including being distributed such that portions of functions areimplemented at different physical locations by one or more physicaldevices. In some examples, base station communications manager 815and/or at least some of its various sub-components may be a separate anddistinct component in accordance with various aspects of the presentdisclosure. In other examples, base station communications manager 815and/or at least some of its various sub-components may be combined withone or more other hardware components, including but not limited to anI/O component, a transceiver, a network server, another computingdevice, one or more other components described in the presentdisclosure, or a combination thereof in accordance with various aspectsof the present disclosure.

Base station communications manager 815 may transmit, to a UE 115,signaling that indicates a UE-specific initial shift to be applied to abase sequence for transmission of an uplink control message and receiveuplink control information in the uplink control message, where theuplink control information is based on a shifted sequence that isshifted with respect to the base sequence in accordance with theUE-specific initial shift and a payload of the uplink controlinformation.

Transmitter 820 may transmit signals generated by other components ofthe device. In some examples, the transmitter 820 may be collocated witha receiver 810 in a transceiver module. For example, the transmitter 820may be an example of aspects of the transceiver 1135 described withreference to FIG. 11. The transmitter 820 may utilize a single antennaor a set of antennas.

FIG. 9 shows a block diagram 900 of a wireless device 905 that supportsUE shift randomization for uplink control channel transmission inaccordance with aspects of the present disclosure. Wireless device 905may be an example of aspects of a wireless device 805 or a base station105 as described with reference to FIG. 8. Wireless device 905 mayinclude receiver 910, base station communications manager 915, andtransmitter 920. Wireless device 905 may also include a processor. Eachof these components may be in communication with one another (e.g., viaone or more buses).

Receiver 910 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to UE shiftrandomization for uplink control channel transmission, etc.).Information may be passed on to other components of the device. Thereceiver 910 may be an example of aspects of the transceiver 1135described with reference to FIG. 11. The receiver 910 may utilize asingle antenna or a set of antennas.

Base station communications manager 915 may be an example of aspects ofthe base station communications manager 1115 described with reference toFIG. 11. Base station communications manager 915 may also include shiftsignaling component 925 and control message manager 930.

Shift signaling component 925 may transmit, to a UE 115, signalingindicative of a UE-specific initial shift to be applied to a basesequence for transmission of an uplink control message. In some cases,shift signaling component 925 may transmit signaling to different UEs115, where the signaling may be indicative of different UE-specificinitial shifts to be applied to the base sequence by each of thedifferent UEs 115 such that interference between transmissions of uplinkcontrol messages is randomized. In some cases, transmitting signalingindicative of the UE-specific initial shift includes transmitting anexplicit indication of the UE-specific initial shift.

In some cases, the explicit indication is included within ARI bits of aDCI message. In some cases, a number of the ARI bits is sufficientlylarge such that two raised to the number of the ARI bits is greater thana number of resources configured for the uplink control message. In somecases, transmitting signaling indicative of the UE-specific initialshift includes transmitting a downlink grant control message having aCCE index from which the UE-specific initial shift is derived. In somecases, transmitting signaling indicative of the UE-specific initialshift includes transmitting an explicit indication of a subset ofresources configured for the uplink control message. In some cases, theexplicit indication is included within ARI bits of a DCI message and anumber of the ARI bits is such that two raised to the number of the ARIbits is less than a number of the resources configured for the uplinkcontrol message.

Control message manager 930 may receive, in the uplink control message,a shifted sequence that is shifted with respect to the base sequence inaccordance with the UE-specific initial shift. In some examples, controlmessage manager 930 may receive uplink control information in the uplinkcontrol message, where the uplink control information is based on ashifted sequence that is shifted with respect to the base sequence inaccordance with the UE-specific initial shift and a payload of theuplink control information. In some cases, the uplink control message isformatted as an sPUCCH message having only one or two bits of uplinkcontrol information.

Transmitter 920 may transmit signals generated by other components ofthe device. In some examples, the transmitter 920 may be collocated witha receiver 910 in a transceiver module. For example, the transmitter 920may be an example of aspects of the transceiver 1135 described withreference to FIG. 11. The transmitter 920 may utilize a single antennaor a set of antennas.

FIG. 10 shows a block diagram 1000 of a base station communicationsmanager 1015 that supports UE shift randomization for uplink controlchannel transmission in accordance with aspects of the presentdisclosure. The base station communications manager 1015 may be anexample of aspects of a base station communications manager 1115described with reference to FIGS. 8, 9, and 11. The base stationcommunications manager 1015 may include shift signaling component 1020,control message manager 1025, and downlink control message component1030. Each of these modules may communicate, directly or indirectly,with one another (e.g., via one or more buses).

Shift signaling component 1020 may transmit, to a UE 115, signaling thatindicates a UE-specific initial shift to be applied to a base sequencefor transmission of an uplink control message and transmit additionalsignaling to different UEs 115. In some cases, the additional signalingmay be indicative of different UE-specific initial shifts to be appliedto the base sequence by the different UEs 115 such that interferencebetween transmissions of uplink control messages is randomized.

In some examples, transmitting the signaling that indicates theUE-specific initial shift includes transmitting an explicit indicationof the UE-specific initial shift. In some cases, the explicit indicationis included within ARI bits of a DCI message, where a number of the ARIbits is sufficiently large such that two raised to the number of the ARIbits is greater than a number of resources configured for the uplinkcontrol message. In some cases, transmitting signaling indicative of theUE-specific initial shift includes transmitting a downlink grant controlmessage having a CCE index from which the UE-specific initial shift isderived. In some cases, transmitting signaling indicative of theUE-specific initial shift includes transmitting an explicit indicationof a subset of resources configured for the uplink control message. Insome cases, the explicit indication is included within ARI bits of a DCImessage. In some cases, a number of the ARI bits is such that two raisedto the number of the ARI bits is less than a number of the resourcesconfigured for the uplink control message.

Control message manager 1025 may receive, in the uplink control message,a shifted sequence that is shifted with respect to the base sequence inaccordance with the UE-specific initial shift. In some cases, the uplinkcontrol message is formatted as an sPUCCH message having only one or twobits of uplink control information.

Downlink control message component 1030 may transmit a downlink grantcontrol message having a CCE index, such that an RB index and shiftindex for the UE-specific initial shift is able to be derived based onthe CCE index as applied to the subset of resources.

FIG. 11 shows a diagram of a system 1100 including a device 1105 thatsupports UE shift randomization for uplink control channel transmissionin accordance with aspects of the present disclosure. Device 1105 may bean example of or include the components of base station 105 as describedherein, e.g., with reference to FIG. 1. Device 1105 may includecomponents for bi-directional voice and data communications includingcomponents for transmitting and receiving communications, including basestation communications manager 1115, processor 1120, memory 1125,software 1130, transceiver 1135, antenna 1140, network communicationsmanager 1145, and inter-station communications manager 1150. Thesecomponents may be in electronic communication via one or more buses(e.g., bus 1110). Device 1105 may communicate wirelessly with one ormore UEs 115.

Processor 1120 may include an intelligent hardware device, (e.g., ageneral-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, anFPGA, a programmable logic device, a discrete gate or transistor logiccomponent, a discrete hardware component, or any combination thereof).In some cases, processor 1120 may be configured to operate a memoryarray using a memory controller. In other cases, a memory controller maybe integrated into processor 1120. Processor 1120 may be configured toexecute computer-readable instructions stored in a memory to performvarious functions (e.g., functions or tasks supporting UE shiftrandomization for uplink control channel transmission).

Memory 1125 may include RAM and ROM. The memory 1125 may storecomputer-readable, computer-executable software 1130 includinginstructions that, when executed, cause the processor to perform variousfunctions described herein. In some cases, the memory 1125 may contain,among other things, a BIOS which may control basic hardware or softwareoperation such as the interaction with peripheral components or devices.

Software 1130 may include code to implement aspects of the presentdisclosure, including code to support UE shift randomization for uplinkcontrol channel transmission. Software 1130 may be stored in anon-transitory computer-readable medium such as system memory or othermemory. In some cases, the software 1130 may not be directly executableby the processor but may cause a computer (e.g., when compiled andexecuted) to perform functions described herein.

Transceiver 1135 may communicate bi-directionally, via one or moreantennas, wired, or wireless links as described herein. For example, thetransceiver 1135 may represent a wireless transceiver and maycommunicate bi-directionally with another wireless transceiver. Thetransceiver 1135 may also include a modem to modulate the packets andprovide the modulated packets to the antennas for transmission, and todemodulate packets received from the antennas. In some cases, thewireless device may include a single antenna 1140. However, in somecases, the device may have more than one antenna 1140, which may becapable of concurrently transmitting or receiving multiple wirelesstransmissions.

Network communications manager 1145 may manage communications with thecore network (e.g., via one or more wired backhaul links). For example,the network communications manager 1145 may manage the transfer of datacommunications for client devices, such as one or more UEs 115.

Inter-station communications manager 1150 may manage communications withother base station 105, and may include a controller or scheduler forcontrolling communications with UEs 115 in cooperation with other basestations 105. For example, the inter-station communications manager 1150may coordinate scheduling for transmissions to UEs 115 for variousinterference mitigation techniques such as beamforming or jointtransmission. In some examples, inter-station communications manager1150 may provide an X2 interface within a Long Term Evolution(LTE)/LTE-A wireless communication network technology to providecommunication between base stations 105.

FIG. 12 shows a flowchart illustrating a method 1200 for UE shiftrandomization for uplink control channel transmission in accordance withaspects of the present disclosure. The operations of method 1200 may beimplemented by a UE 115 or its components as described herein. Forexample, the operations of method 1200 may be performed by a UEcommunications manager as described with reference to FIGS. 4 through 7.In some examples, a UE 115 may execute a set of codes to control thefunctional elements of the device to perform the functions describedherein. Additionally or alternatively, the UE 115 may perform aspects ofthe functions described herein using special-purpose hardware.

At 1205 the UE 115 may identify a base sequence for transmission of anuplink control message. The operations of 1205 may be performedaccording to the methods described herein. In certain examples, aspectsof the operations of 1205 may be performed by a sequence manager asdescribed with reference to FIGS. 4 through 7.

At 1210 the UE 115 may receive signaling that indicates a UE-specificinitial shift to be used with the base sequence. The operations of 1210may be performed according to the methods described herein. In certainexamples, aspects of the operations of 1210 may be performed by arandomized shift component as described with reference to FIGS. 4through 7.

At 1215 the UE 115 may determine uplink control information for theuplink control message. The operations of 1215 may be performedaccording to the methods described herein. In certain examples, aspectsof the operations of 1230 may be performed by a control messagetransmission component as described with reference to FIGS. 4 through 7.

At 1220 the UE 115 may determine a shifted sequence of the base sequencebased at least in part on the UE-specific initial shift and the uplinkcontrol information. The operations of 1220 may be performed accordingto the methods described herein. In certain examples, aspects of theoperations of 1220 may be performed by a sequence manager as describedwith reference to FIGS. 4 through 7.

At 1225 the UE 115 may transmit the uplink control information in theuplink control message, where the uplink control information is based onthe shifted sequence. The operations of 1225 may be performed accordingto the methods described herein. In certain examples, aspects of theoperations of 1225 may be performed by a control message transmissioncomponent as described with reference to FIGS. 4 through 7.

FIG. 13 shows a flowchart illustrating a method 1300 for UE shiftrandomization for uplink control channel transmission in accordance withaspects of the present disclosure. The operations of method 1300 may beimplemented by a base station 105 or its components as described herein.For example, the operations of method 1300 may be performed by a basestation communications manager as described with reference to FIGS. 8through 11. In some examples, a base station 105 may execute a set ofcodes to control the functional elements of the device to perform thefunctions described herein. Additionally or alternatively, the basestation 105 may perform aspects of the functions described herein usingspecial-purpose hardware.

At 1305 the base station 105 may transmit, to a UE 115, signaling thatindicates a UE-specific initial shift to be applied to a base sequencefor transmission of an uplink control message. The operations of 1305may be performed according to the methods described herein. In certainexamples, aspects of the operations of 1305 may be performed by a shiftsignaling component as described with reference to FIGS. 8 through 11.

At 1310 the base station 105 may receive uplink control information inthe uplink control message, where the uplink control information isbased on a shifted sequence that is shifted with respect to the basesequence in accordance with the UE-specific initial shift and a payloadof the uplink control information. The operations of 1310 may beperformed according to the methods described herein. In certainexamples, aspects of the operations of 1310 may be performed by acontrol message manager as described with reference to FIGS. 8 through11.

It should be noted that the methods described herein describe possibleimplementations, and that the operations and the steps may be rearrangedor otherwise modified and that other implementations are possible.Further, aspects from two or more of the methods may be combined.

Techniques described herein may be used for various wirelesscommunications systems such as code division multiple access (CDMA),time division multiple access (TDMA), frequency division multiple access(FDMA), orthogonal frequency division multiple access (OFDMA), singlecarrier frequency division multiple access (SC-FDMA), and other systems.A CDMA system may implement a radio technology such as CDMA2000,Universal Terrestrial Radio Access (UTRA), etc. CDMA2000 covers IS-2000,IS-95, and IS-856 standards. IS-2000 Releases may be commonly referredto as CDMA2000 1×, 1×, etc. IS-856 (TIA-856) is commonly referred to asCDMA2000 1×EV-DO, High Rate Packet Data (HRPD), etc. UTRA includesWideband CDMA (WCDMA) and other variants of CDMA. A TDMA system mayimplement a radio technology such as Global System for MobileCommunications (GSM).

An OFDMA system may implement a radio technology such as Ultra MobileBroadband (UMB), Evolved UTRA (E-UTRA), Institute of Electrical andElectronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE802.20, Flash-OFDM, etc. UTRA and E-UTRA are part of Universal MobileTelecommunications System (UMTS). LTE, LTE-A, and LTE-A Pro are releasesof UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, LTE-A Pro, NR,and GSM are described in documents from the organization named “3rdGeneration Partnership Project” (3GPP). CDMA2000 and UMB are describedin documents from an organization named “3rd Generation PartnershipProject 2” (3GPP2). The techniques described herein may be used for thesystems and radio technologies mentioned above as well as other systemsand radio technologies. While aspects of an LTE, LTE-A, LTE-A Pro, or NRsystem may be described for purposes of example, and LTE, LTE-A, LTE-APro, or NR terminology may be used in much of the description, thetechniques described herein are applicable beyond LTE, LTE-A, LTE-A Pro,or NR applications.

A macro cell generally covers a relatively large geographic area (e.g.,several kilometers in radius) and may allow unrestricted access by UEs115 with service subscriptions with the network provider. A small cellmay be associated with a lower-powered base station 105, as comparedwith a macro cell, and a small cell may operate in the same or different(e.g., licensed, unlicensed, etc.) frequency bands as macro cells. Smallcells may include pico cells, femto cells, and micro cells according tovarious examples. A pico cell, for example, may cover a small geographicarea and may allow unrestricted access by UEs 115 with servicesubscriptions with the network provider. A femto cell may also cover asmall geographic area (e.g., a home) and may provide restricted accessby UEs 115 having an association with the femto cell (e.g., UEs 115 in aclosed subscriber group (CSG), UEs 115 for users in the home, and thelike). An eNB for a macro cell may be referred to as a macro eNB. An eNBfor a small cell may be referred to as a small cell eNB, a pico eNB, afemto eNB, or a home eNB. An eNB may support one or multiple (e.g., two,three, four, and the like) cells, and may also support communicationsusing one or multiple component carriers.

The wireless communications system 100 or systems described herein maysupport synchronous or asynchronous operation. For synchronousoperation, the base stations 105 may have similar frame timing, andtransmissions from different base stations 105 may be approximatelyaligned in time. For asynchronous operation, the base stations 105 mayhave different frame timing, and transmissions from different basestations 105 may not be aligned in time. The techniques described hereinmay be used for either synchronous or asynchronous operations.

Information and signals described herein may be represented using any ofa variety of different technologies and techniques. For example, data,instructions, commands, information, signals, bits, symbols, and chipsthat may be referenced throughout the above description may berepresented by voltages, currents, electromagnetic waves, magneticfields, optical fields, particles, or any combination thereof.

The various illustrative blocks and modules described in connection withthe disclosure herein may be implemented or performed with ageneral-purpose processor, a digital signal processor (DSP), anapplication-specific integrated circuit (ASIC), a field-programmablegate array (FPGA) or other programmable logic device (PLD), discretegate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described herein.A general-purpose processor may be a microprocessor, but in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices (e.g., a combinationof a DSP and a microprocessor, multiple microprocessors, one or moremicroprocessors in conjunction with a DSP core, or any other suchconfiguration).

The functions described herein may be implemented in hardware, softwareexecuted by a processor, firmware, or any combination thereof. Ifimplemented in software executed by a processor, the functions may bestored on or transmitted over as one or more instructions or code on acomputer-readable medium. Other examples and implementations are withinthe scope of the disclosure and appended claims. For example, due to thenature of software, functions described herein can be implemented usingsoftware executed by a processor, hardware, firmware, hardwiring, orcombinations of any of these. Features implementing functions may alsobe physically located at various positions, including being distributedsuch that portions of functions are implemented at different physicallocations.

Computer-readable media includes both non-transitory computer storagemedia and communication media including any medium that facilitatestransfer of a computer program from one place to another. Anon-transitory storage medium may be any available medium that can beaccessed by a general purpose or special purpose computer. By way ofexample, and not limitation, non-transitory computer-readable media maycomprise random-access memory (RAM), read-only memory (ROM),electrically erasable programmable read only memory (EEPROM), flashmemory, compact disk (CD) ROM or other optical disk storage, magneticdisk storage or other magnetic storage devices, or any othernon-transitory medium that can be used to carry or store desired programcode means in the form of instructions or data structures and that canbe accessed by a general-purpose or special-purpose computer, or ageneral-purpose or special-purpose processor. Also, any connection isproperly termed a computer-readable medium. For example, if the softwareis transmitted from a website, server, or other remote source using acoaxial cable, fiber optic cable, twisted pair, digital subscriber line(DSL), or wireless technologies such as infrared, radio, and microwave,then the coaxial cable, fiber optic cable, twisted pair, DSL, orwireless technologies such as infrared, radio, and microwave areincluded in the definition of medium. Disk and disc, as used herein,include CD, laser disc, optical disc, digital versatile disc (DVD),floppy disk and Blu-ray disc where disks usually reproduce datamagnetically, while discs reproduce data optically with lasers.Combinations of the above are also included within the scope ofcomputer-readable media.

As used herein, including in the claims, “or” as used in a list of items(e.g., a list of items prefaced by a phrase such as “at least one of” or“one or more of”) indicates an inclusive list such that, for example, alist of at least one of A, B, or C means A or B or C or AB or AC or BCor ABC (i.e., A and B and C). Also, as used herein, the phrase “basedon” shall not be construed as a reference to a closed set of conditions.For example, an exemplary step that is described as “based on conditionA” may be based on both a condition A and a condition B withoutdeparting from the scope of the present disclosure. In other words, asused herein, the phrase “based on” shall be construed in the same manneras the phrase “based at least in part on.”

In the appended figures, similar components or features may have thesame reference label. Further, various components of the same type maybe distinguished by following the reference label by a dash and a secondlabel that distinguishes among the similar components. If just the firstreference label is used in the specification, the description isapplicable to any one of the similar components having the same firstreference label irrespective of the second reference label, or othersubsequent reference label.

The description set forth herein, in connection with the appendeddrawings, describes example configurations and does not represent allthe examples that may be implemented or that are within the scope of theclaims. The term “exemplary” used herein means “serving as an example,instance, or illustration,” and not “preferred” or “advantageous overother examples.” The detailed description includes specific details forthe purpose of providing an understanding of the described techniques.These techniques, however, may be practiced without these specificdetails. In some instances, well-known structures and devices are shownin block diagram form in order to avoid obscuring the concepts of thedescribed examples.

The description herein is provided to enable a person skilled in the artto make or use the disclosure. Various modifications to the disclosurewill be readily apparent to those skilled in the art, and the genericprinciples defined herein may be applied to other variations withoutdeparting from the scope of the disclosure. Thus, the disclosure is notlimited to the examples and designs described herein, but is to beaccorded the broadest scope consistent with the principles and novelfeatures disclosed herein.

What is claimed is:
 1. A method for wireless communication at a userequipment (UE), comprising: identifying a base sequence for transmissionof an uplink control message; receiving signaling that indicates aUE-specific initial shift to be used with the base sequence; determininga number of bits associated with hybrid automatic repeat request (HARQ)feedback in a payload of uplink control information for the uplinkcontrol message; determining a shifted sequence of the base sequencebased at least in part on the UE-specific initial shift and the numberof bits associated with the HARQ feedback in the payload of the uplinkcontrol information; and transmitting the uplink control information inthe uplink control message, wherein the uplink control message is basedat least in part on the shifted sequence.
 2. The method of claim 1,further comprising: identifying that the payload of the uplink controlinformation is one of a scheduling request (SR), a one-bitacknowledgement, or a two-bit acknowledgement; and determining theshifted sequence based at least in part on the payload.
 3. The method ofclaim 2, wherein the uplink control message is formatted as a shortphysical uplink control channel message, and wherein the payload of theuplink control information comprises the one-bit acknowledgment or thetwo-bit acknowledgment.
 4. The method of claim 2, wherein the payload ofthe uplink control information comprises the one-bit acknowledgment, andwherein determining the shifted sequence comprises: determining theshifted sequence based at least in part on a shift value thatcorresponds to the payload of the uplink control information, the shiftvalue comprising a value of 0 or
 6. 5. The method of claim 2, whereinthe uplink control information comprises the two-bit acknowledgment, andwherein determining the shifted sequence comprises: determining theshifted sequence based at least in part on a shift value thatcorresponds to the payload of the uplink control information, the shiftvalue comprising a value of 0, 3, 6, or
 9. 6. The method of claim 1,wherein receiving the signaling that indicates the UE-specific initialshift comprises: receiving an explicit indication of the UE-specificinitial shift.
 7. The method of claim 6, wherein the explicit indicationis included within acknowledgement (ACK) resource indicator (ARI) bitsof a downlink control information (DCI) message or a radio resourcecontrol (RRC) message.
 8. The method of claim 7, wherein two raised to anumber of the ARI bits is greater than a number of resources configuredfor the uplink control message.
 9. The method of claim 1, whereinreceiving the signaling that indicates the UE-specific initial shiftcomprises: receiving a downlink grant control message having a controlchannel element (CCE) index from which the UE-specific initial shift isderived.
 10. The method of claim 9, further comprising: deriving aresource block (RB) index and a shift index for the UE-specific initialshift based at least in part on the CCE index of the downlink grantcontrol message.
 11. The method of claim 1, wherein receiving thesignaling that indicates the UE-specific initial shift comprises:receiving an explicit indication of a subset of resources configured forthe uplink control message; receiving a downlink grant control messagehaving a control channel element (CCE) index; and deriving a resourceblock (RB) index and a shift index for the UE-specific initial shiftbased at least in part on the CCE index as applied to the subset ofresources.
 12. The method of claim 11, wherein the explicit indicationis included within acknowledgement (ACK) resource indicator (ARI) bitsof a downlink control information (DCI) message or a radio resourcecontrol (RRC) message.
 13. The method of claim 12, wherein two raised toa number of the ARI bits is less than a number of resources configuredfor the uplink control message.
 14. The method of claim 1, furthercomprising: determining one or more shifted sequences of the basesequence based at least in part on the UE-specific initial shift and theuplink control information; and selecting the shifted sequence from theone or more shifted sequences based at least in part on the payload ofthe uplink control information.
 15. The method of claim 14, furthercomprising: randomizing the selecting of the shifted sequence from theone or more shifted sequences.
 16. A method for wireless communicationat a base station, comprising: transmitting, to a user equipment (UE),signaling that indicates a UE-specific initial shift to be applied to abase sequence for transmission of an uplink control message; andreceiving uplink control information in the uplink control message,wherein the uplink control message is based at least in part on ashifted sequence that is shifted with respect to the base sequence inaccordance with the UE-specific initial shift and a number of bitsassociated with hybrid automatic repeat request (HARD) feedback in apayload of the uplink control information.
 17. The method of claim 16,wherein the uplink control message is formatted as a short physicaluplink control channel message, and wherein the payload of the uplinkcontrol information comprises a one-bit acknowledgment or a two-bitacknowledgment.
 18. The method of claim 16, wherein transmitting thesignaling that indicates the UE-specific initial shift comprises:transmitting an explicit indication of the UE-specific initial shift.19. The method of claim 18, wherein the explicit indication is includedwithin acknowledgement (ACK) resource indicator (ARI) bits of a downlinkcontrol information (DCI) message or a radio resource control (RRC)message.
 20. The method of claim 19, wherein two raised to a number ofthe ARI bits is greater than a number of resources configured for theuplink control message.
 21. The method of claim 16, further comprising:transmitting additional signaling to different UEs, the additionalsignaling indicating different UE-specific initial shifts to be appliedto the base sequence by each of the different UEs, wherein interferencebetween transmissions of uplink control messages is randomized based atleast in part on the different UE-specific initial shifts.
 22. Themethod of claim 16, wherein transmitting the signaling that indicatesthe UE-specific initial shift comprises: transmitting a downlink grantcontrol message having a control channel element (CCE) index from whichthe UE-specific initial shift is derived.
 23. The method of claim 16,wherein transmitting the signaling that indicates the UE-specificinitial shift comprises: transmitting an explicit indication of a subsetof resources configured for the uplink control message; and transmittinga downlink grant control message having a control channel element (CCE)index, wherein a resource block (RB) index and shift index for theUE-specific initial shift is able to be derived based at least in parton the CCE index as applied to the subset of resources.
 24. The methodof claim 23, wherein the explicit indication is included withinacknowledgement (ACK) resource indicator (ARI) bits of a downlinkcontrol information (DCI) message or a radio resource control (RRC)message.
 25. The method of claim 24, wherein two raised to a number ofthe ARI bits is less than a number of resources configured for theuplink control message.
 26. An apparatus for wireless communication,comprising: a processor, memory coupled with the processor; andinstructions stored in the memory and executable by the processor tocause the apparatus to: identify a base sequence for transmission of anuplink control message; receive signaling that indicates a userequipment (UE)-specific initial shift to be used with the base sequence;determine a number of bits associated with hybrid automatic repeatrequest (HARQ) feedback in a payload of uplink control information forthe uplink control message; determine a shifted sequence of the basesequence based at least in part on the UE-specific initial shift and thenumber of bits associated with the HARQ feedback in the payload of theuplink control information; and transmit the uplink control informationin the uplink control message, wherein the uplink control message isbased at least in part on the shifted sequence.
 27. The apparatus ofclaim 26, wherein the instructions are further executable by theprocessor to cause the apparatus to: identify that the payload of theuplink control information is one of a scheduling request (SR), aone-bit acknowledgement, or a two-bit acknowledgement; and determine theshifted sequence based at least in part on the payload.
 28. Theapparatus of claim 27, wherein the uplink control message is formattedas a short physical uplink control channel message, and wherein thepayload of the uplink control information comprises the one-bitacknowledgment or the two-bit acknowledgment.
 29. The apparatus of claim27, wherein the payload of the uplink control information comprises theone-bit acknowledgment, and comprises: determine the shifted sequencebased at least in part on a shift value that corresponds to the payloadof the uplink control information, the shift value comprising a value of0 or
 6. 30. The apparatus of claim 27, wherein the uplink controlinformation comprises the two-bit acknowledgment, and comprises:determine the shifted sequence based at least in part on a shift valuethat corresponds to the payload of the uplink control information, theshift value comprising a value of 0, 3, 6, or
 9. 31. The apparatus ofclaim 26, wherein the instructions to receive the signaling thatindicates the UE-specific initial shift are executable by the processorto cause the apparatus to: receive an explicit indication of theUE-specific initial shift.
 32. The apparatus of claim 31, wherein theexplicit indication is included within acknowledgement (ACK) resourceindicator (ARI) bits of a downlink control information (DCI) message ora radio resource control (RRC) message.
 33. The apparatus of claim 32,wherein two raised to a number of the ARI bits is greater than a numberof resources configured for the uplink control message.
 34. Theapparatus of claim 26, wherein the instructions to receive the signalingthat indicates the UE-specific initial shift are executable by theprocessor to cause the apparatus to: receive a downlink grant controlmessage having a control channel element (CCE) index from which theUE-specific initial shift is derived.
 35. The apparatus of claim 34,wherein the instructions are further executable by the processor tocause the apparatus to: derive a resource block (RB) index and a shiftindex for the UE-specific initial shift based at least in part on theCCE index of the downlink grant control message.
 36. The apparatus ofclaim 26, wherein the instructions to receive the signaling thatindicates the UE-specific initial shift are executable by the processorto cause the apparatus to: receive an explicit indication of a subset ofresources configured for the uplink control message; receive a downlinkgrant control message having a control channel element (CCE) index; andderive a resource block (RB) index and a shift index for the UE-specificinitial shift based at least in part on the CCE index as applied to thesubset of resources.
 37. The apparatus of claim 36, wherein the explicitindication is included within acknowledgement (ACK) resource indicator(ARI) bits of a downlink control information (DCI) message or a radioresource control (RRC) message.
 38. The apparatus of claim 37, whereintwo raised to a number of the ARI bits is less than a number ofresources configured for the uplink control message.
 39. The apparatusof claim 26, wherein the instructions are further executable by theprocessor to cause the apparatus to: determine one or more shiftedsequences based at least in part on the UE-specific initial shift andthe uplink control information; and select the shifted sequence from theone or more shifted sequences based at least in part on the payload ofthe uplink control information.
 40. The apparatus of claim 39, whereinthe instructions are further executable by the processor to cause theapparatus to: randomize the selecting of the shifted sequence from theone or more shifted sequences.
 41. An apparatus for wirelesscommunication, comprising: a processor, memory coupled with theprocessor; and instructions stored in the memory and executable by theprocessor to cause the apparatus to: transmit, to a user equipment (UE),signaling that indicates a UE-specific initial shift to be applied to abase sequence for transmission of an uplink control message; and receiveuplink control information in the uplink control message, wherein theuplink control message is based at least in part on a shifted sequencethat is shifted with respect to the base sequence in accordance with theUE-specific initial shift and a number of bits associated with hybridautomatic repeat request (HARQ) feedback in a payload of the uplinkcontrol information.
 42. The apparatus of claim 41, wherein the uplinkcontrol message is formatted as a short physical uplink control channelmessage, and wherein the payload of the uplink control informationcomprises a one-bit acknowledgment or a two-bit acknowledgment.
 43. Theapparatus of claim 41, wherein the instructions to transmit thesignaling that indicates the UE-specific initial shift are executable bythe processor to cause the apparatus to: transmit an explicit indicationof the UE-specific initial shift.
 44. The apparatus of claim 43, whereinthe explicit indication is included within acknowledgement (ACK)resource indicator (ARI) bits of a downlink control information (DCI)message or a radio resource control (RRC) message.
 45. The apparatus ofclaim 44, wherein two raised to a number of the ARI bits is greater thana number of resources configured for the uplink control message.
 46. Theapparatus of claim 41, wherein the instructions are further executableby the processor to cause the apparatus to: transmit additionalsignaling to different UEs, the additional signaling indicatingdifferent UE-specific initial shifts to be applied to the base sequenceby each of the different UEs, wherein interference between transmissionsof uplink control messages is randomized based at least in part on thedifferent UE-specific initial shifts.
 47. The apparatus of claim 41,wherein the instructions to transmit the signaling that indicates theUE-specific initial shift are executable by the processor to cause theapparatus to: transmit a downlink grant control message having a controlchannel element (CCE) index from which the UE-specific initial shift isderived.
 48. The apparatus of claim 41, wherein the instructions totransmit the signaling that indicates the UE-specific initial shift areexecutable by the processor to cause the apparatus to: transmit anexplicit indication of a subset of resources configured for the uplinkcontrol message; and transmit a downlink grant control message having acontrol channel element (CCE) index, wherein a resource block (RB) indexand shift index for the UE-specific initial shift is able to be derivedbased at least in part on the CCE index as applied to the subset ofresources.
 49. The apparatus of claim 48, wherein the explicitindication is included within acknowledgement (ACK) resource indicator(ARI) bits of a downlink control information (DCI) message or a radioresource control (RRC) message.
 50. The apparatus of claim 49, whereintwo raised to a number of the ARI bits is less than a number ofresources configured for the uplink control message.
 51. An apparatusfor wireless communication, comprising: means for identifying a basesequence for transmission of an uplink control message; means forreceiving signaling that indicates a user equipment (UE)-specificinitial shift to be used with the base sequence; means for determining anumber of bits associated with hybrid automatic repeat request (HARQ)feedback in a payload of uplink control information for the uplinkcontrol message; means for determining a shifted sequence of the basesequence based at least in part on the UE-specific initial shift and thenumber of bits associated with the HARQ feedback in the payload of theuplink control information; and means for transmitting the uplinkcontrol information in the uplink control message, wherein the uplinkcontrol message is based at least in part on the shifted sequence. 52.The apparatus of claim 51, further comprising: means for identifyingthat the payload of the uplink control information is one of ascheduling request (SR), a one-bit acknowledgement, or a two-bitacknowledgement; and means for determining the shifted sequence based atleast in part on the payload.
 53. The apparatus of claim 52, wherein theuplink control message is formatted as a short physical uplink controlchannel message, and wherein the payload of the uplink controlinformation comprises the one-bit acknowledgment or the two-bitacknowledgment.
 54. The apparatus of claim 52, wherein the payload ofthe uplink control information comprises the one-bit acknowledgment, andcomprises: means for determining the shifted sequence based at least inpart on a shift value that corresponds to the payload of the uplinkcontrol information, the shift value comprising a value of 0 or
 6. 55.The apparatus of claim 52, wherein the uplink control informationcomprises the two-bit acknowledgment, and comprises: means fordetermining the shifted sequence based at least in part on a shift valuethat corresponds to the payload of the uplink control information, theshift value comprising a value of 0, 3, 6, or
 9. 56. The apparatus ofclaim 51, wherein the means for receiving the signaling that indicatesthe UE-specific initial shift comprises: means for receiving an explicitindication of the UE-specific initial shift.
 57. An apparatus forwireless communication at a base station, comprising: means fortransmitting, to a user equipment (UE), signaling that indicates aUE-specific initial shift to be applied to a base sequence fortransmission of an uplink control message; and means for receivinguplink control information in the uplink control message, wherein theuplink control message is based at least in part on a shifted sequencethat is shifted with respect to the base sequence in accordance with theUE-specific initial shift and a number of bits associated with hybridautomatic repeat request (HARQ) feedback in a payload of the uplinkcontrol information.
 58. The apparatus of claim 57, wherein the uplinkcontrol message is formatted as a short physical uplink control channelmessage, and wherein the payload of the uplink control informationcomprises a one-bit acknowledgment or a two-bit acknowledgment.
 59. Theapparatus of claim 57, wherein the means for transmitting the signalingthat indicates the UE-specific initial shift comprises: means fortransmitting an explicit indication of the UE-specific initial shift.60. The apparatus of claim 57, further comprising: means fortransmitting additional signaling to different UEs, the additionalsignaling indicating different UE-specific initial shifts to be appliedto the base sequence by each of the different UEs, wherein interferencebetween transmissions of uplink control messages is randomized based atleast in part on the different UE-specific initial shifts.
 61. Anon-transitory computer-readable medium storing code for wirelesscommunication, the code comprising instructions executable by aprocessor to: identify a base sequence for transmission of an uplinkcontrol message; receive signaling that indicates a user equipment(UE)-specific initial shift to be used with the base sequence; determinea number of bits associated with hybrid automatic repeat request (HARQ)feedback in a payload of uplink control information for the uplinkcontrol message; determine a shifted sequence of the base sequence basedat least in part on the UE-specific initial shift and the number of bitsassociated with the HARQ feedback in the payload of the uplink controlinformation; and transmit the uplink control information in the uplinkcontrol message, wherein the uplink control message is based at least inpart on the shifted sequence.
 62. A non-transitory computer-readablemedium storing code for wireless communication, the code comprisinginstructions executable by a processor to: transmit, to a user equipment(UE), signaling that indicates a UE-specific initial shift to be appliedto a base sequence for transmission of an uplink control message; andreceive uplink control information in the uplink control message,wherein the uplink control message is based at least in part on ashifted sequence that is shifted with respect to the base sequence inaccordance with the UE-specific initial shift and a number of bitsassociated with hybrid automatic repeat request (HARQ) feedback in apayload of the uplink control information.